Begin by whisking together 1 cup of almond flour and 1 ½ cups of powdered sugar in a large bowl until well combined and airy.

In another large bowl, whip 3 egg whites and ¼ teaspoon cream of tartar using a hand mixer on medium speed until the mixture becomes bubbly and forms soft peaks.

Gradually add in ¾ cup of granulated sugar while continuing to whip, then increase the speed to high and beat until it reaches stiff, glossy peaks, about 5-7 minutes.

Carefully fold half of the prepared almond flour mixture into the meringue, then add the remaining dry mixture and continue folding until just combined.

Divide the macaron batter into two bowls; mix one with teal gel food coloring and leave the second bowl white, folding until colors are uniform.

Fit a piping bag with a round tip, fill it with the colored batter, and pipe 1.5-inch circles on a silicone baking mat, sprinkling colorful sprinkles on the white shells.

Let the piped macaron shells rest at room temperature for 30-45 minutes while preheating the oven to 295°F (145°C).

Bake the shells for 15-16 minutes or until firm, then allow them to cool on a wire rack.

Beat ½ cup of softened butter until creamy, then mix in 2 cups of powdered sugar, ¼ cup of white cake mix, and 2 tablespoons of heavy whipping cream along with 1 teaspoon of vanilla extract.

Pipe an even layer of buttercream onto the flat side of each teal macaron shell, top with a matching white shell, and refrigerate for 24 hours before serving.