Preheat oven to 300°F (150°C). Line a baking sheet with parchment paper.
Sift almond flour and powdered sugar together.
In a mixing bowl, beat egg whites until foamy. Gradually add granulated sugar and continue to beat until stiff peaks form.
Fold in the almond flour mixture into the egg whites until well combined.
Transfer the batter to a piping bag and pipe small circles onto the prepared baking sheet.
Tap the baking sheet on the counter to release any air bubbles. Let the macarons sit at room temperature for 30 minutes to form a skin.
Bake for 15 minutes. Let cool completely before removing from the parchment paper.
For the filling, beat the butter until creamy. Gradually add powdered sugar and vanilla extract. Pipe or spread the filling onto the flat side of a macaron and sandwich with another macaron.