Make the Cookie Dough:
In a large bowl, beat the butter and sugar until light and fluffy. Add the egg, vanilla extract, and almond extract (if using), and mix until combined.
In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Chill the Dough:
Divide the dough into two discs, wrap in plastic wrap, and refrigerate for at least 1 hour.

Preheat the Oven:
Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper.

Roll and Cut the Cookies:
On a lightly floured surface, roll out the dough to about 1/4-inch thickness. Use a mitten-shaped cookie cutter to cut out the cookies. Place them on the prepared baking sheets.

Bake:
Bake for 8-10 minutes, or until the edges are lightly golden. Let the cookies cool on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely.

Make the Icing:
In a medium bowl, whisk together the powdered sugar, milk or cream, and vanilla extract until smooth. Divide the icing into separate bowls and tint with food coloring as desired.

Decorate:
Use a piping bag or small spoon to decorate the cookies with icing. Add sprinkles or edible glitter while the icing is still wet. Let the icing set completely before serving.