Preheat the oven to 350 degrees F, and line baking sheets with silicone mats or parchment paper, set aside. In a small mixing bowl combine the flour, baking powder, and salt. Stir to combine, set aside.
In a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment, cream the butter on medium speed until fluffy, 3-4 minutes. Add in the powdered sugar and mix for another 2-3 minutes until creamy. Add in the vanilla, almond, and egg, mixing to combine.
Add in the dry ingredients and mix on low until combined. The dough should be tacky but not too sticky, if it is too sticky add an extra tablespoon or two of flour.
Transfer the dough onto a floured surface and roll out to about 1/4" thick. Use cookie cutters to cut into desired shapes. Transfer to the prepared baking sheets, and bake for 8-11 minutes until slightly golden brown the cookies will still be slightly soft*. Allow to cool slightly before transferring to a wire rack. Allow to cool before frosting.
For the Frosting:
In the bowl of a stand mixer or if using a hand mixer, a large mixing bowl, cream the softened butter until light and fluffy, about 2-3 minutes. Add in the vanilla extract and heavy cream, mix to combine.
With the mixer on low add in 1/2 a cup of powdered sugar at a time, mixing until combined each time. Continue to add powdered sugar until you have reached a desired consistency, you may not need all 4 cups.
Spread or pipe the frosting onto the cooled cookies, decorate with colored sugar or sprinkles as desired!
Notes
*Baking time is dependent on the size/shape and thickness of cookies. If making smaller cookies reduce baking time.