In a medium bowl, beat the egg whites until frothy.
2. Step
Keep beating and slowly add sugar until stiff peaks form.
3. Step
Sift powdered sugar, cookie crumbs, almond flour, and cocoa powder over the egg whites.
4. Step
Fold the dry mixture into the egg whites completely, but make sure to not overmix or the macarons will not rise.
5. Step
Once the batter reaches a lava-like consistency, add the food coloring. Mix until just combined, without over mixing.
6. Step
Preheat oven to 285ºF (140ºC).
7. Step
Place the mixture into a piping bag or zip-top bag. Cut of the tip to pipe.
8. Step
Pipe 1½-inch (4 cm) dollops onto a baking sheet lined with parchment paper. Tip: take a little batter to “glue” down the edges of the parchment paper so it stays put.
9. Step
Let the cookies rest at room temperature for 30 minutes to an hour, until they are no longer wet to the touch and a skin forms on top.
10. Step
While resting, make the filling by mixing the butter, powdered sugar, cookie cream filling, vanilla, and milk in a bowl until smooth.
11. Step
Transfer to a piping bag and set aside until ready to fill.
12. Step
When the cookies are dry to the touch, bake for 15-18 minutes until they have risen.
13. Step
Let rest for 10 minutes before filling.
14. Step
To fill, pipe about about a tablespoon of the buttercream onto one macaron and place another on top.
15. Step
Macarons are best kept refrigerated until serving.
