In a medium bowl, whisk together the gluten-free flour blend, baking powder, and salt. Set aside.

In a large bowl of a stand mixer fitted with the paddle attachment, cream together the softened butter and granulated sugar on medium speed until light and fluffy, about 2-3 minutes.

Beat in the egg, then the vanilla extract and almond extract (if using), scraping down the sides of the bowl as needed, until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined and a soft dough forms. Be careful not to overmix.

Divide the dough in half. Flatten each half into a disc, wrap tightly in plastic wrap, and refrigerate for at least 1 hour, or up to 24 hours. Chilling is crucial for easy rolling and to prevent spreading.

Preheat your oven to 375°F (190°C). Line two baking sheets with parchment paper.

On a lightly floured surface (using gluten-free flour), roll out one disc of chilled dough to about 1/4-inch thickness.

Cut out shapes with your favorite cookie cutters. Carefully transfer the cut cookies to the prepared baking sheets, leaving about 1 inch between each cookie. Re-roll any scraps until all dough is used.

Bake for 8-10 minutes, or until the edges are lightly golden and the centers are set. Baking time may vary slightly depending on cookie size and oven.

Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. Repeat with the second dough disc.

In a small bowl, whisk together the sifted powdered sugar, 2 tablespoons of milk/water, vanilla extract, and salt until smooth. Add more liquid 1/2 teaspoon at a time if needed to reach a thick yet pourable consistency.

Once cookies are completely cool, decorate as desired with the royal icing. Allow icing to set fully before stacking or storing.