Make the Macaron Shells:

1. Sift together the almond flour and powdered sugar into a large bowl. Discard any large lumps.
2. In a separate bowl, beat the egg whites with cream of tartar until foamy.
3. Gradually add the granulated sugar while beating on medium speed until stiff, glossy peaks form.
4. Gently fold in the peppermint extract and red gel food coloring (if using).
5. Fold the dry ingredients into the meringue using a spatula. Mix until the batter flows like lava—smooth and glossy, but not runny. This is called the macaronage stage.
6. Transfer the batter to a piping bag fitted with a round tip.
7. Pipe small circles (about 1½ inches in diameter) onto a parchment-lined baking sheet. Tap the sheet firmly on the counter to release air bubbles.
8. Let the macarons rest at room temperature for 30–60 minutes, or until a skin forms and they are no longer sticky to the touch.
9. Preheat the oven to 300°F (150°C) and bake for 14–16 minutes. The macarons are done when they have formed “feet” and easily lift off the parchment when cooled.
10. Cool completely before filling.

Make the Peppermint Buttercream:

1. In a bowl, beat the softened butter until creamy.
2. Gradually add the powdered sugar, beating until smooth and fluffy.
3. Mix in the peppermint extract and heavy cream, beating until light and spreadable.
4. Transfer the buttercream to a piping bag.

Assemble the Macarons:

1. Pair up matching macaron shells.
2. Pipe a small dollop of peppermint buttercream onto one shell.
3. Gently sandwich with another shell, pressing lightly to spread the filling evenly.
4. Optionally, roll the edges in crushed peppermint candies for extra crunch and festive flair.
5. Refrigerate the macarons for 24 hours to allow the flavors to meld, then bring to room temperature before serving.