Preheat oven to 325 degrees.
Prepare two large pipping bags with a round tip with about a 1/4" opening (Ateco #804 is what I use) and a baking sheet lined with parchment paper.
In a medium bowl, sift almond flour and powdered sugar together. Set aside.
In a stand mixer with a whisk attachment, beat egg whites on high speed until they form soft peaks.
Lower the mixer's speed to medium and add sugar.
Put mixer back on the highest speed and beat until they form stiff peaks.
With the mixer still on high speed, add 5 or 6 drops of bright white food coloring.
Take bowl off of mixer and add almond flour/sugar mixture.
Using a rubber spatula, aggressively fold in dry ingredients until the batter starts to loosen and becomes a little runny. To test if the batter is ready, lift a small amount of batter from the bowl and drop it back into the batter. If it does nothing, keep mixing. If it slowly melts back into the batter after 20-30 seconds, it is ready.
Cover the mixture with plastic wrap, and pour a little bit of pink, purple, and blue food coloring onto a piece of parchment.
With a small paintbrush, dip the brush into the pink food coloring, and then randomly paint the inside of the bag.
Wash the brush, and repeat with remaining colors.
Put 1/2 the batter into prepared piping bag and cover the rest of the batter with plastic wrap.
Pipe 1 1/2" circles on prepared baking sheet and firmly tap the bottom of the tray so the batter flattens out.
Repaint a new bag and repeat with remaining batter.
Let them rest for 30-45 minutes until they form a skin.
Bake for 10-12 minutes, or until they are set.
Let cool before peeling them off parchment paper.
Once they are cool, peel macarons off parchment paper and pair them according to size.
Use paint brush to paint the top of the shell with piping gel and then add edible glitter.