Preheat the oven to 275°F (135°C).

Line two baking sheets with silicone mats or parchment paper.

Sift together ground almonds and powdered sugar.

Whip the egg whites until stiff peaks form, adding granulated sugar gradually.

Fold the almond mixture into the egg whites carefully.

Pipe small rounds onto prepared baking sheets and let rest for 20 to 40 minutes.

Bake for about 15 minutes and allow to cool.

Cream together butter and powdered sugar, then add lemon juice and vanilla for the filling.

Assemble the macarons with the filling.

Let the assembled macarons rest in the refrigerator for at least 24 hours.