Directions

1. sift together the almond flour, powdered sugar, and ground blueberries. set the dry ingredients aside.
2. put your egg whites and a pinch of the sugar into the bowl of a stand mixer fitted with the whisk attachment. whisk on medium-high speed until you see soft peaks. then, with the mixer on low, slowly add in the rest of the sugar and the food coloring, then turn the mixer up to high speed. whisk the mixture until it has stiff peaks.
3. now, add your dry ingredients to the egg mixture all at once. with a spatula or a wooden spoon, fold it all together - at first it will seem like the dry ingredients won't incorporate, but just keep folding. you want to keep folding until the batter is "lava-like" - basically, it should fall from the spatula in thick ribbons that slowly ooze back into the rest of the batter.