Sift the almond flour and powdered sugar together into a bowl to remove any lumps.
In another bowl, beat the egg whites until frothy, then gradually add granulated sugar and continue to beat until stiff peaks form. Add food coloring if desired.
Fold the dry ingredients into the egg whites gently until the batter forms a "lava-like" consistency.
Pipe small circles of batter onto a lined baking sheet and let them rest for 20–30 minutes to form a skin.
Bake at 150°C (300°F) for 15–18 minutes. Let cool completely before adding fillings.