In a large bowl or the bowl of a stand mixer, beat the sugar, butter, and cream cheese until well blended. Add the almond extract, vanilla extract, and egg yolk, and mix until combined.
Add the flour and salt, and mix to form a soft dough. Shape the dough into a ball and wrap it in plastic wrap. Refrigerate for at least 2 hours, until firm.
When ready to bake, preheat the oven to 375°F. Line 3 baking sheets with parchment or silicone liners.
Use a rolling pin to roll the dough out on a lightly floured surface to ¼-inch thick. Cut the dough into desired shapes with cookie cutters (or the top of a cup), placing one inch apart on prepared cookie sheets.
Bake 8-10 minutes, until light golden brown around the edges. Let cool completely before frosting.