Line baking sheets with parchment paper or silicone mats.

Sift powdered sugar and almond flour together in a bowl. Discard any large chunks left in the sifter.

In a separate bowl, beat the egg whites until frothy. Gradually add granulated sugar while beating until stiff peaks form. Add food coloring and flavor extracts if desired.

Gently fold the almond flour mixture into the egg whites until just combined. Be careful not to overmix.

Transfer the batter to a piping bag fitted with a round tip. Pipe small circles onto the prepared baking sheets, spacing them about 1 inch apart.

Tap the baking sheets firmly on the counter to release any air bubbles. Let the macarons sit at room temperature for 30 minutes to 1 hour, until a skin forms on top.

Preheat the oven to 300°F (150°C). Bake the macarons for 15-18 minutes, rotating the pans halfway through, until the tops are set and the bottoms are just beginning to brown.

Let the macarons cool completely on the baking sheets before gently removing them.

Pair up macaron shells of similar size and shape. Fill one half of each pair with your desired filling (such as ganache, buttercream, or jam), then sandwich with the other half.

Refrigerate the filled macarons for 24 hours before serving to allow the flavors to meld together. Enjoy!