1. Preheat your oven to 300°F (150°C). Line a baking sheet with parchment paper or a silicone baking mat.
2. Sift together almond flour and powdered sugar to ensure a smooth batter.
3. In a clean, dry bowl, beat the egg whites until foamy. Gradually add granulated sugar and continue beating until stiff, glossy peaks form.
4. Gently fold the sifted dry ingredients into the egg whites, adding a few drops of blue gel food coloring gradually to achieve a vibrant, uniform blue hue.
5. Transfer the batter to a piping bag fitted with a round tip and pipe small, uniform circles onto the prepared baking sheet.
6. Tap the baking sheet gently to release air bubbles, then let the macarons rest for 30-60 minutes until a skin forms.
7. Bake for 15-20 minutes until the shells are firm. Allow to cool completely before removing from the baking sheet.

Filling and Assembly

1. Prepare your filling: either vanilla buttercream or blueberry jam, depending on your preference.
2. Spread or pipe the filling onto one macaron shell, then top with a second shell to create a sandwich.
3. Optional: Decorate with edible glitter or a light dusting of blue food coloring for that galaxy-inspired look.