Instructions

1. Prepare two baking sheets by placing two macaron baking mats on each sheet. Set baking sheets aside.
2. Place the oven rack in the lower half of the oven, but not all the way to the bottom. Preheat oven to 315 degrees.
3. Add powdered sugar, cookie crumbs, egg white powder, and almond flour to the large mixing bowl. Process the ingredients for about 30 seconds so that the mixture is super fine.
4. In the bowl of a stand mixer with a whisk attachment, add egg whites and beat on medium-high until it begins to foam. Once it starts to get foamy, begin to slowly sprinkle the granulated sugar into the egg whites until it's all been incorporated. Increase the speed to high to whip the meringue into stiff peaks.
5. Once the meringue is done, add it to the bowl of the flour mixture. Do this step very carefully and slowly, cutting the mixture down the middle and swooping around. Mix just until it's incorporated. Do not over-mix. The consistency should be like slow-moving lava. To check for consistency, the batter should flow from your spatula like thick lava and hold a ribbon for a couple of seconds. If it falls into clumps and doesn't fall slowly, it is not mixed enough. Keep mixing slowly so that the batter deflates a bit and the proper consistency is reached.
6. Transfer the batter to a piping bag fitted with a smooth, round 1/2-inch tip. Holding the bag in two hands directly over the parchment, pipe a small amount of batter into the first circle stencil. Stop pipping right as the batter reaches the edge of the circle. The batter will spread so don't add too much. Move on to the other circles until all the batter is gone.
7. After you've pipped all the circles, smack the baking sheets on the counter a couple of times to release air bubbles. Use a toothpick to pop all the air bubbles. If you don't do this step, the air bubbles will release steam while baking and crack the shells.
8. Let them sit to dry out until the tops are smooth to the touch, about 30 minutes. They are done when you rub your finger over the top and your finger doesn't stick.
9. Bake macarons in the preheated oven, one sheet at a time for 10-12 minutes. Make sure to rotate the sheet halfway through, for even baking. Remove from oven and let them cool for 5 minutes before transferring parchment sheet to a wire rack to finish cooling.
10. While the macarons cool, make the cookies & cream buttercream.
11. Add to a piping bag with your desired tip.
12. Lay half of the macarons flat side up on a baking sheet. Pipe a small quarter-sized amount of buttercream in the center of one shell. Top with the other shell and gently press just enough to push the filling out to the edges. Do this for all the macaron shells until done.
13. Melt the chocolate chips in the microwave and drizzle across the top of the macarons. Then, sprinkle on some Oreo cookie crumbs.
14. Once filled, macarons can be refrigerated in an airtight container for up to three days or frozen for 3 months.