Instructions

1. Preheat the oven to 300°F (150°C) and line two baking sheets with parchment paper.
2. In a food processor, combine the almond flour and 1 3/4 cups of powdered sugar. Process until finely ground and well mixed.
3. In a large bowl, beat the egg whites until foamy. Add the cream of tartar and continue to beat until soft peaks form.
4. Gradually add the granulated sugar, while continuing to beat the egg whites. Beat until stiff peaks form and the mixture is glossy.
5. Add the vanilla extract and food coloring, if using, and beat until just combined.
6. Gradually add the almond flour mixture to the egg whites, folding gently until just combined. Be careful not to deflate the mixture; it should flow like lava.
7. Transfer the mixture to a piping bag fitted with a round tip. Pipe small circles (about 1.5 inches in diameter) onto the prepared baking sheets, leaving space between each.
8. Let the macarons sit at room temperature for 30-60 minutes, until they form a skin and are no longer sticky to the touch.
9. Bake the macarons for 15-20 minutes, rotating the baking sheets halfway through, until they are set and have formed 'feet'. Let them cool completely on the baking sheets.
10. Meanwhile, prepare the buttercream filling. In a medium bowl, beat the softened butter until creamy. Gradually add the 3 cups of powdered sugar and beat until smooth. Add the vanilla extract and mix well.
11. Once the macarons are cool, pipe or spread the buttercream filling onto the flat side of one macaron shell. Top with another shell to create a sandwich. Repeat with the remaining macarons and filling.