In a medium bowl, whisk together the gluten-free flour blend, baking powder, baking soda, and salt until well mixed.

In a large mixing bowl, beat the room temperature unsalted butter and sugar together until light and fluffy.

Add the egg whites and vanilla extract to the butter-sugar mixture, and beat until smooth and creamy.

Gradually add the dry mixture to the wet ingredients, mixing gently until a dough forms.

Use a piping bag or spoon to drop small dollops of dough onto a parchment-lined baking sheet.

Preheat your oven to 350°F (175°C) and bake for about 20 minutes, or until lightly golden brown.

Let the cookies cool on the baking sheet for a few minutes before transferring them to a wire rack.