Transform a mediocre boxed cake mix into a super moist, bakery-worthy birthday cake that everyone will be asking the recipe for! Bake in a 9x13 pan and top with an easy cream cheese frosting for the best "homemade" doctored sheet cake!
More fun birthday cake ideas: Try my Ice Cream Sandwich Cake or 9ร13 Zebra Cake!

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Why I Love This Doctored White Cake:
- It's So Moist: This white sheet cake is super moist and has the perfect, dense cake crumb. Unlike a regular cake mix that is fluffy and crumbles when cut, then once slices perfectly!
- It's A Nice Tall Sheet Cake: In my opinion, most box mixes don't produce enough batter for a tall sheet cake. But by adding our secret ingredients, you get a tall, substantial 9x13 cake!
- It's Full of Flavor: The added vanilla and almond extract give this a true white wedding cake flavor that blows any regular boxed mix out of the water!
- Perfect for: Kid's Birthday Cakes, Baby Shower Cakes, Bridal Shower Cake, DIY Wedding Cake, Mother's Day Cake
New! Use this same recipe to make Strawberry Jello Poke Cake!
Yes, start with a cake mix!
I've used this recipe for years but have always been hesitant to post it because the #haters will say that starting with a boxed cake mix is cheating. But guess what, if that's considered cheating then I guess I love cheating.
Because when it tastes this DANG GOOD and better than any from-scratch cake I've ever made, I don't care if it started with a box mix. Besides, in case you didn't know, a lot of real bakeries actually use cake mix as their base (I once saw the backroom of my favorite bakery and lined on the shelves were cake mixes LOL). It's the PERFECT, cheap way to make a bakery-quality cake without spending $20 at the grocery store.
Plus, I am not a fan of most grocery store frosting. This, however, you'll be licking off your finger. I recommend and prefer Pillsbury White "Moist Supreme" but I've also used other brands with a similar result.
Delicious Cream Cheese Frosting
Ditch the canned frosting and top this with a vanilla almond cream cheese frosting to take this cake up a notch! You can also use a traditional buttercream frosting if you want a sturdier, more pipeable frosting but I much prefer the taste of this cream cheese frosting!
Ingredients for the Best Sheet Cake:
- 15.25 ounce White Boxed Cake Mix (I recommend and prefer Pillsbury White Moist Supreme)
- Flour
- Sugar
- Sour Cream
- Egg Whites (save the yolks for tomorrow's scrambled eggs!)
- Vanilla extract
- Water
- Frosting: Cream cheese, powdered, sugar, vanilla extract, and almond extract
Notice that this recipe requires NO oil, butter or pudding mix! Even without those standard ingredients, this cake transforms into the perfect dense crumb, wedding cake texture and taste. For extra fruity flavor, make my Strawberry Jello Poke Cake.
How to Make White Sheet Cake:
Step 1: Mix Batter
Start by mixing the dry ingredients with a whisk. Once combined, mix in the egg whites, sour cream, and water and continue mixing until combined. You can use an electric mixer, but whisking by hand works well for this recipe.
Step 2: Pour in 9x13 Pan & Bake
Pour batter in greased 9x13 metal pan and bake for 28-30 minutes or until toothpick comes out clean. The edges should look *slightly* brown but you don't want it to darken too much.
If you use the Pillsbury cake mix, the top always bake nice and flat (not domed) which makes it easy to decorate!
Step 3: Cool & Frost
Allow cake to completely cool before frosting.
My personal favorite frosting for this white cake is my delectable cream cheese frosting (recipe below). Itโs not too sweet and is the perfect pairing with these vanilla cupcakes. If you want a more pipeable frosting, try out a buttercream frosting instead.
Frequently Asked Questions:
What brand of cake mix do you recommend?
I used and prefer Pillsbury White (Moist Supreme) but Iโve tried it with several other mixes and it works fine.
Whatโs the difference between this recipe and a cake mix straight-out-of-the-box?
You might be thinking, โwhatโs so different about this recipe if you are still using a boxed cake mix?โ Well, I will tell you. The secret is sour cream and egg whites. Yes, sour cream ainโt just for baked potatoes anymore. It is used to moisten many types of cakes/batters and any time Iโve used it, the result has always been amazing. And the egg whites? Since you are removing fat content (by taking out the yolk), you need to use the sour cream to balance that back out to produce a soft & moist cake.
Tip: Save the egg yolks in a plastic bowl (covered with saran wrap) and toss into a big batch of scrambled eggs in the morning. Or use the liquid egg whites you can buy in a carton to avoid having leftover egg yolks.
Can I make these into cupcakes?
Yes! If you want to turn these into cupcakes, you can bake them for 18-20 minutes. I have that step-by-step in my White Wedding Cupcake post.
If you're looking for a pipeable frosting for cupcakes, you can use my Buttercream Frosting recipe instead of the cream cheese one (although I personally like the cream cheese better!).
Do I have to refrigerate this cake?
If you're making the cream cheese frosting, you will want to refrigerate the cake if sitting out for more than 1-2 hours.
You can also freeze white cake for up to a month by wrapping in plastic wrap and storing in airtight container. Any longer and your cake might dry out.
What if I don't have almond extract?
I will say that almond extract does give this cake the best flavor but if you don't have it, you could substitute for extra vanilla extract or lemon extract.
The BEST White Sheet Cake (Doctored Cake Mix!)
Ingredients
9x13 White Cake
- 1 15.25 ounce box white cake mix I prefer Pillsbury Moist Supreme
- 1 cup all-purpose flour
- ยฝ cup granulated sugar
- 1 teaspoon vanilla extract
- 1 ยฝ cups water
- ยพ cup sour cream
- 4 large egg whites (equal to ยฝ cup if using liquid carton egg whites)
Cream Cheese Frosting
- ยฝ cup unsalted butter softened
- 4ย ounces ย cream cheese softened
- 1 teaspoon vanilla extract
- ยผ teaspoon almond extract
- 1 ยผ cup powdered sugar add more for stiffer frosting
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.
Instructions
- Preheat oven to 325ยฐF.
- In a large bowl or stand mixer, whisk together white cake mix (15.25 ounce), all-purpose flour (1 cup), and granulated sugar (ยฝ cup).
- Once incorporated, add in the vanilla extract (1 teaspoon), water (1 ยฝ cups), sour cream (ยพ cup), and egg whites (ยฝ cup, or 4 large eggs) one at a time until combined. Do not whip the cake mix; just mix until everything is incorporated."
- Pour batter into greased 9x13 metal pan and bake for 28-30 minutes or until toothpick or fork come out clean.
- Allow to cool completely before frosting.
To Make Cream Cheese Frosting:
- In a large bowl, beat the softened unsalted butter (ยฝ cup, i.e. 1 stick) and softened cream cheese (4 ounces) on medium speed using a hand or stand mixer (with paddle attachment) for 2-3 minutes (until light and creamy).
- Keeping the mixer on medium speed, slowly add in vanilla extract (1 teaspoon), almond extract (ยผ teaspoon) and powdered sugar (1 ยผ cups). Once incorporated, turn mixer to high speed and beat for 2 minutes until creamy.
- Spread on cooled cake and top with sprinkles!
- If not enjoying immediately or within 1-2 hours, refrigerate cake until serving.
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.
Notes
- Looking for a more pipe-able, fluffy frosting? Try my Buttercream Frosting recipe instead!
- If you don't have almond extract you can substitute for extra vanilla or even lemon extract. Although I do think almond extract gives the best flavor!
- You can turn these in cupcakes by baking for 18-20 minutes. Recipe yields 24 standard sized cupcakes.
- I used and prefer Pillsbury White (Moist Supreme) but Iโve tried it with several other mixes and it works fine.
Nutrition
Did you make these cookies? Be sure to leave a comment below with how you liked them!
Melissa says
Great recipe on both cake and frosting.
I would highly recommend this recipe.
Melissa says
So glad you enjoyed the recipe! Thank you so much for leaving a review, Melissa!
Janice says
Can you freeze this cake?
Melissa says
Yes, you can freeze it but I would recommend waiting to frost it until after it's thawed or else the frosting can get a little sticky. For the cake, I also recommend letting it "breathe" a bit while thawing so that the moisture doesn't all get trapped inside the plastic wrap or container. It's a very moist cake as-is, so I do think it's best fresh but can be frozen!
Joan Egizii says
Best white cake recipe ever. Shared a portion with my neighbor and she was so impressed. Iโll try this recipe using other flavors of cake mix, absolutely delicious!!
Melissa says
So happy to hear you loved this recipe, Joan! Thank you so much for taking the time to leave a review!
Debbie says
Best White Cake EVER! And so easy. Thanks you for the recipe.
Mitzi says
Best white cake I have ever made...and from a cake mix!! Wonderful! Everyone loved it!!
Melissa says
So happy to hear everyone loved the recipe! Thank you so much for taking the time to leave a review!
MBBB says
Great cake ; very moist and not too sweet. I took e lazy route and mixed ready made chocolate frosting with cream cheese, a bit of salt and added icing sugar. It is still delicious!
Marilynn says
This is a good recipe I will use again thankyou
Pizzavitals says
Perfect recipe
Ericka Young says
Will this work for 6" pans to layer?
Melissa says
Yeah just bake for less time!
Velma Elizabth Button says
excellent myfamily and friends loved it.
Melissa says
So glad to hear everyone loved it! Thank you so much for leaving a review, Velma!
Lisa Groeschner says
It was not cooked all the way in the middle. I would not make again.
Melissa says
Sorry this didn't work for you! What brand of cake mix did you use & do you use an internal oven thermometer to ensure your oven is at the correct heat?
Lala says
You won't make it again because you didn't cook it all the way through? I don't understand. Is the recipe faulty somehow?
Candy says
It is delicious! I made it for our church bazaar and people asked for the recipe! One thing they couldn't get over was how nice and thick it was!
Melissa says
Thank you so much for leaving a review, Candy! So happy to hear everyone loved the recipe! :)
FRANCES DOMINGOS says
I'm not a fan of this cake. To start, I made many wedding cakes in the 80s and 90s, but my specialty was custom decorated cakes. I made hundreds and I used cake mixes, Duncan Hines being my go-to mix. I know mixes are used in commercial bakeries. A cousin of mine had a bakery and her cake mixes came in 50lb sacks, not boxes. I have an event coming up and decided to take my decorating equipment out of storage. I searched for a doctored white cake mix recipe. This one sounded good. The results were not as good as anticipated. Moist? Somewhat, but not in a good way. It was definitely not fluffy, as if that's a bad thing. In my opinion, it was more dense and heavy than moist, not like a pound cake, which was what I was hoping for. The texture was more coarse. When I tasted it after cooling and before frosting, I could taste the added flour. I used a butter cream frosting and that helped cover the floury taste. If there are other flour-added recipes out there I'll avoid them. I'll keep looking for a recipe and experimenting. Frankly, if I need to, I'll just use a white cake mix as-is.
Melissa says
Sorry that you didn't love this!
Lisa Groeschner says
What is the time for baking if I do two 9-inch pans instead of a sheet pan?
Melissa says
I would start at 22 minutes and test doneness with a toothpick every few minutes.
Teresa Turnbull says
I followed your recipe except I added 1 cup of water and 1/2 cup oil. I also added sprinkles because my grandkids love them. Cake is baking so I hope for the best!
Cb says
Iโm sorry. This cake was dry, hard, and flavorless. It was a waste of time and ingredients.
Melissa says
Sorry this didn't work out for you!