In a large bowl, whisk flour, baking powder, and salt until combined.
In another large bowl, using a handheld mixer on medium-high speed, beat butter and sugar until fluffy and pale in color. Add egg, milk, and vanilla and beat until combined. Gradually add dry ingredients and beat on medium-low speed until combined and no dry streaks remain.
On a clean work surface, shape into a disk and wrap in plastic wrap. Refrigerate 1 hour.
Preheat oven to 350º. On a lightly floured surface, roll dough to ⅛" thick. Cut out shapes and transfer to 2 parchment-lined baking sheets. Freeze 10 minutes (so your shapes hold while baking!).
Bake cookies until edges are lightly golden, 8 to 10 minutes.
In a large bowl, using handheld mixer on medium-high speed, beat butter until smooth, then add confectioners' sugar and beat until no lumps remain. Add cream, almond extract, and salt and beat until combined.
Bake cookies until edges are lightly golden, 8 to 10 minutes. Let cool.
Frost and decorate cookies as desired.
