Turn my viral cosmic brownie recipe into these adorable & easy Christmas tree brownies, inspired by the Little Debbie version! Bake in a 9×13 pan and cut in triangles to make the perfect bite-sized brownies that are perfect for holiday dessert platters!
Why I Love These Tree Brownies
- Fudgy Brownie Base: This is my TikTok viral cosmic brownie recipe that has over 500 five-star reviews…but made to look like the Little Debbie Christmas tree brownies! It’s a super rich, fudgy brownie topped with white chocolate ganache (with cute little rainbow chip sprinkles for ornaments!).
- Easy to cut: Use my photo references below to show you how you can cut a 9×13 pan into 24 brownies! No cookie cutters needed!
- Perfect for holiday platters: Add some variety to your holiday cookie platters with these bite-sized brownie trees!
Ingredient Notes & Tips
For more ingredient notes & tips, read through my original cosmic brownie recipe for a more extensive list!
- Homemade or boxed brownies: While you can use your favorite brownie recipe, my from-scratch recipe for copycat cosmic brownies is below!
- White chocolate chips: To get the iconic green color, we’re using white chocolate chips, heavy cream, and food coloring. Different brands of white chocolate chips can perform differently due to the type of fat content they have. I tested these with both Ghiradelli and Kroger “Private Selection” brands and both taste great and develop a firm ganache. Nestle brand works okay but doesn’t firm up as well. If you’re making boxed brownies, you can also warm a can of vanilla frosting, add food coloring, then pour it over the brownies.
- Green food coloring: I recommend gel-based food coloring so that you don’t have to use a lot to get a dark green color (some liquid-based coloring can make the chocolate seize). You can typically find gel food coloring like Betty Crocker at grocery stores (I found it at Aldi) or Wilton gel coloring on Amazon or at craft stores.
- Rainbow chip sprinkles: I get these on Amazon but you can also typically find them at craft stores. Pillsbury also recently came out with a brownie mix that includes a packet of rainbow chip sprinkles (and is a good cheap option that you can find at most grocery stores!).
Make it gluten-free! Use your favorite gluten-free flour to make these gluten-free! My favorite brand is Bob’s Red Mill Gluten Free 1-to-1 Baking Flour.
How to Make Cosmic Brownie Trees:
This is just an overview showing step-by-step photos, jump down to full recipe card with exact instructions.
Step 1: Make Brownies
Use the recipe below or simply bake your favorite boxed brownies! I highly recommend both greasing and lining the pan with a parchment paper sling so that you can easily lift them out of the pan for cutting.
Step 2: Decorate & Refrigerate
Make the white chocolate ganache and use food coloring to dye it green. Pour on top of the brownies, use a spatula to spread, then top with rainbow chip sprinkles. Refrigerate for 1-2 hours or until the ganache is firm.
Tip: In order to get clean cuts, be sure to refrigerate until your ganache is firm before cutting! This often takes 1-2 hours in the fridge.
Step 3: Cut into Triangles
Run a knife along the edges of the brownies (that aren’t covered with parchment), then carefully lift the brownie slab out of the pan. Use the instructions & photo references below to cut.
- Use a large, straight-edged knife to cut the brownies in half horizontally, then cut each half into half again.
- Starting on the bottom quadrant, use a sharp knife to cut into triangles. To keep clean edges, wipe the knife off on a warm, wet cloth in between each cut (or whenever the ganache is sticking to the knife).
- Continue until all brownies are cut (you should get 24 brownie trees). You can snack on the edge pieces.
Tips & Tricks
- Bake in a light-colored metal pan & be sure not to overbake! It’s important not to overbake these brownies (which glass or dark metal pans can do!) to ensure they don’t become dry and/or bitter. Check to make sure they are done by inserting a toothpick into the middle or gently shaking the pan to ensure the center is not jiggly. If the toothpick comes out clean, then they are finished baking. If you bake them too long, they won’t have the irresistible fudgy texture you want.
- Refrigerate to set the ganache: I tested 11 batches of this ganache to get a perfect consistency (see my notes on brands below) as white chocolate ganache can be more difficult to set. After decorating, allow your brownies to chill in the fridge to help them firm up. Right after you remove it & let it sit out at room temperature, the ganache may seem a bit tacky but will firm up as it comes to room temperature.
- Don’t skip the parchment! Lining the pan with a parchment sling will allow you to get these clean cuts; it will be very difficult to cut these in the pan itself.
Storing & Freezing
Storing: Ganache can stay at room temperature for 2 days but I recommend storing in the fridge to be safe. These cosmic brownies also get fudgier on Day 2 after being in the fridge, so I highly recommend keeping them chilled!
Freezing: If you want to freeze, wait to add the ganache until after freezing and thawing. I don’t recommend freezing the frosted brownies, as condensation will form on the ganache and it will make the colors of the sprinkles bleed.
Frequently Asked Questions:
I get rainbow chip sprinkles on Amazon but you can also typically find them at craft stores. Pillsbury also recently came out with a “funfetti” brownie mix that includes a packet of rainbow chip sprinkles (and is a good cheap option that you can find at most grocery stores!).
Different brands of white chocolate chips can perform differently due to the type of fat content they have. I tested these with both Ghiradelli and Kroger “Private Selection” brands and both taste great and develop a firm ganache. Nestle brand works okay but doesn’t firm up as well.
The tricks are to (a) make sure the ganache is chilled & firm, (b) make sure you use a parchment sling (see photo below) so that you can easily lift the brownies out of the pan for cutting, and (c) wipe your knife off between cuts. The parchment sling will allow you to lift the brownies out and use a large knife and cut across without the pan getting in the way. Wiping the knife off on a warm, wet cloth in between each cut (or whenever the ganache is sticking to the knife) will prevent smearing and crumbs.
Start by adding white chocolate chips to a glass or heat-proof bowl. Microwave the heavy cream for 1.5 minutes (be sure to place it in a large glass measuring cup or heat-safe bowl so that it has room to expand upwards). Pour the hot cream over the white chocolate chips but don’t stir. Allow to sit for about 1 minute, then use a fork to stir; it will be thick and will likely look like it’s going to mix together but keep at it for at least 30 seconds. At this point, the mixture will likely be thick and look a little grainy. Microwave in 15-second increments on 50% power, stirring in between each until smooth and pourable (I did four rounds of this).
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Cosmic Christmas Tree Brownies
Turn my viral cosmic brownie recipe into these adorable & easy Christmas tree brownies, inspired by the Little Debbie version! Bake in a 9×13 pan and cut in triangles to make the perfect bite-sized brownies that are perfect for holiday dessert platters1
- ¾ cup unsalted butter (i.e 1 ½ sticks; you will be melting this)
- 1 ½ cups granulated sugar
- ½ cup light brown sugar
- 3 large eggs + 1 egg yolk
- 1 tablespoon vanilla extract
- 1 teaspoon salt
- ¼ teaspoon baking soda
- 2 tablespoons cornstarch
- 1 ½ cups Hershey's cocoa powder (100% cacao natural unsweetened) I highly recommend using this specific cocoa or another quality cocoa. Off-brand cocoa often tastes bad so use at your own risk…you've been warned!
- 1 cup all-purpose flour
- ¼ cup vegetable oil
White Chocolate Ganache
- 2 cups white chocolate chips (i.e 11 or 12 oz. bag) I like the taste of Ghiradelli the best, see FAQ section above for notes on brands
- ⅓ cup + 2 tablespoons heavy cream
- green food coloring
- Rainbow chip sprinkles see tips in post above for where to buy locally
Before you begin! If you make this, will you do me a huge favor and leave a review and rating letting me know how you liked this recipe? This helps my small business thrive so I can continue providing free recipes and high-quality content for you.
To Make Brownies:
Before you start, be sure to read through the tips & tricks in the post above for ingredient notes, step-by-step photos, and FAQ's!
In a large microwave-safe bowl, add unsalted butter (¾ cup, i.e. 1 ½ sticks), granulated sugar (1 ½ cups), and light brown sugar (½ cup). Microwave for 2 minutes, stir, then micowave for 30 more seconds. Carefully remove bowl from microwave and stir until smooth. Let cool for 2-3 minutes.
To the butter and sugar mixture, stir in the 3 whole eggs, 1 extra egg yolk, vanilla extract (1 tablespoon), salt (1 teaspoon), baking soda (¼ teaspoon), and cornstarch (2 tablespoons). Once combined, mix in cocoa powder (1 ½ cups) and all-purpose flour (1 cup) until just combined (I recommend mixing by hand to prevent overmixing). Stir in vegetable oil (¼ cup).
Spray a light metal 9×13 pan with nonstick cooking spray, then press on a piece of parchment paper to cover the bottom and long sides to create a parchment sling (photo in faq section above!). This will help you lift the brownies out of the pan so that you can cut them nicely. Spread brownie batter into the prepared pan until smooth.
Note: baking these in glass or dark metal pans may cause them to overbake and become bitter. If that's the only pan you have, lining with parchment on all sides becomes more crucial. You will also likely need to bake them for less time to prevent overbaking.
To Make White Chocolate Ganache:
In a medium-sized, heat-safe bowl, place white chocolate chips (2 cups; i.e. 11 or 12oz bag).
In a separate medium-sized bowl or large liquid measuring cup, heat heavy cream (⅓ cup + 2 tablespoons) in the microwave for 1 ½ minutes, or until it begins to bubble (it’s important that your measuring cup or bowl is at least 4x taller than the milk line, as it will expand when it’s heating and can easily overflow). You can also heat this on the stove; remove it once it begins to steam.
Use a hot pad to carefully remove milk from the microwave and pour over the white chocolate chips (do not stir yet!). Use a fork to press down the chips so that they're fully covered with the cream.
Allow to sit for about 1 minute, then use a fork to stir; it will be thick and will likely look like it's going to mix together but keep at it for at least 30 seconds. At this point, the mixture will likely be thick and look a little grainy. Microwave in 15-second increments on 50% power, stirring in between each until smooth and pourable (I did four rounds of this).
Stir in green food coloring, then pour over cooled brownies and spread until smooth. Tap the pan on the counter to help smooth out any bumps.
Immediately top with rainbow chip sprinkles (or any other sprinkles you have!). Place in refrigerator for 1-2 hours to help the ganache harden (you can speed this up by putting in the freezer!).
Use a large knife to slice bars into trees, as shown in the photo instructions in the blog post above. I highly recommend that your bars are chilled before slicing to ensure a clean cut.
Storage: I recommend refrigerate the frosted bars, as they get even better & fudgier on Day 2! You can also keep them at room temperature for up to 2 days, if desired.
Last Step! Please leave a review and rating letting me know how you liked this recipe! This helps my small business thrive so I can continue providing free recipes and high-quality content for you.
Cocoa Powder: I tested this recipe using Hershey’s Unsweetened Cocoa powder, as it’s my favorite cocoa for brownies. Take note that different brands may cause the brownie taste and texture to be a bit different.
White chocolate chips: White chocolate chips can perform differently depending on the brand and type of fat content they have. I tested these with both Ghiradelli and Kroger “Private Selection” brands and both taste great and develop a firm ganache. Nestle brand works okay but doesn’t firm up as well.
Nutrition is just an estimate and calculated with an automated system.
More fun ideas…
How do you doctor up a brownie mix for Christmas??
If you don’t want to make this cosmic brownie version, here are a few other Christmas brownie ideas!
- Boxed Mixed: Use a boxed mix and then pour on warm canned frosting (dyed green) to make an easy version of these! I love Ghiradelli Triple Chocolate boxed mix and then I use 2 boxes for a nice & thick 9×13 pan.
- Sprinkles: Add some Christmas jimmies on top of the brownie batter so that they are baked into the top (and you don’t need to add any frosting!). This is a super easy way to make holiday brownies! You can also decorate like I did above but use rainbow nonpareil sprinkles as the ornaments!
- Bake in a round pan: If you don’t have a 9×13 pan, you could bake two 8×8” round pans and then cut them into slices (they’ll be bigger triangles that look like brownie trees!). Just bake for a little less time since the brownies will be thinner.