Line two sheet pans with parchment paper. Use a 1½-inch round cookie cutter to draw circles on the parchment paper and flip over the paper (drawing side down). Prepare a pastry bag with a round tip with a Wilton 2A.

Using a food processor, pulse the powdered sugar and almond flour. Sift several times until there are less than 2 tablespoons of almond bits left. Add these to the mixture.

In the bowl of an electric mixer with the whisk attachment, combine the egg whites, cream of tartar, and sugar. Whip on medium-high speed until stiff peaks form, about 5-7 minutes.

Add the dry ingredients to the meringue and fold with a rubber spatula. Gently fold to deflate the meringue by pressing against the side of the bowl and scooping from the bottom until the batter is smooth and shiny; about 20-25 folds. To check consistency, drop a spoonful of batter and it should have a peak that quickly relaxes back into the batter. Start checking the batter around 18-20 folds.

Transfer the batter to a pastry bag and pipe the batter into the pre-traced circles on the baking sheet. Tap the baking sheet hard on a counter to release any air bubbles trapped in the batter.

Using a fine sieve, gently sift the finely crushed freeze-dried mango or strawberry powder over the shells. A thin coating of the freeze-dried powder is sufficient.

Let shells sit on a counter for at least 30 minutes and up to 2 hours to dry. When you touch the shells, they should not be sticky.

Preheat oven to 300 degrees F. Bake for 15-20 minutes or until shells harden, rotating cookie sheets halfway through baking time. You should be able to peel off the macaron from the parchment. Cool completely on cookie sheets before peeling from the parchment.

FOR THE FILLING: Whip the butter until light and creamy. Add in the rest of the ingredients and mix on low until combined. Increase speed to low and whip for additional 2-3 minutes.

FOR THE FILLING: Using a pastry bag fitted with a large round or star tip, fill macarons. Store in refrigerator until ready to serve. Allow to get to room temperature before enjoying!