Preheat the oven to 300°F (150°C). Line baking sheets with parchment paper.

In a bowl, sift together almond flour and powdered sugar.

In a separate bowl, whisk egg whites until frothy, then gradually add granulated sugar until stiff peaks form.

Gently fold the almond flour mixture into the egg whites until well combined. Add vanilla extract and food coloring if desired.

Pipe small circles onto the prepared baking sheets and let them sit for 30 minutes to dry.

Bake for about 15-20 minutes, until the shells are firm and dry. Let cool completely.

For the buttercream, beat butter until creamy, then gradually add powdered sugar, lemon juice, and lemon zest until smooth.

Assemble the macarons by spreading lemon buttercream on one shell and blueberry compote on another, then sandwich them together.

Let them rest in the fridge before serving to enhance the flavors.