• Preheat oven to 350°F.
• Place 12 OREOs in a large ziploc bag and use a rolling pin to crush into fine crumbs (or use a food processor). This amount will give you enough for the dough & topping.
• Tip before starting! I will note that this is a thicker dough that is easiest to make with a stand mixer. If you only have a handheld mixer, you may just need to use a spatula to help mix the flour in.
• In a large bowl, use an electric mixer on medium-high speed to cream softened  ¾ cup unsalted butter (i.e. 1 ½ sticks , ¾ cup light brown sugar, and ¾ cup granulated sugar for 2 minutes until light and fluffy.
• Add the 2 large eggs, 2 teaspoons vanilla extract, and 3 tablespoons light corn syrup and mix on low speed until combined. Scrape down the sides of the bowl so everything can combine.
• Add in 1 teaspoon baking powder and ½ teaspoon salt and mix for another 5-10 seconds until combined.
• Lastly, add ¾ cup dark cocoa powder, ¾ cup OREO cookie crumbs and 2 ¼ cup all-purpose flour and mix on medium until combined.
• Spray a light-colored metal 9×13 pan with cooking spray, then line pan with parchment paper, leaving a 2 inch overhang on each long side so that you will be able to lift the bars out of the pan.
• Drop the dough into 1-tablespoon sized chunks into the prepared pan and spread until smooth on top.

  Tip: This dough is a little sticky, so to help spread, I recommend spraying your hands with cookie spray or use place another piece of parchment paper on top and continue pressing down.
• Bake bars at 350°F for 16-20 minutes, or until the center no longer looks wet. The center may look a tiny bit underdone but the bars will continue to bake in the hot pan when cooling.

  Allow to fully cool before decorating.

To Make Chocolate Coating:

• In a large microwave-safe mixing bowl, beat the softened ½ cup unsalted butter (i.e. 1 stick) , 1 teaspoon vanilla extract, and ¼ teaspoon salt on medium-high speed for 1 minute until smooth. Turn the mixer to low speed then slowly add the 3 tablespoons dark cocoa powder and 1 cup powdered sugar. You may need to stop and scrape down the sides. Add 1 tablespoon milk.
• Microwave for 10 seconds to make glossy & easy to spread.
• Spread frosting over cooled cookie bars. Top with remaining ¼ cup OREO crumbs and Gummy worms.
• Allow frosting to firm up before cutting; it's best to refrigerate or freeze for 30 minutes to help set.

  To get clean slices, fill a tall cup with hot water. In between cuts, dip the knife into the water and use a paper towel to dry it off. When cutting, don't "saw" the bars but rather press straight down and gently lift the knife.