Whisk the flour, baking powder, and salt together in a medium bowl. Beat the softened butter and granulated sugar in a separate bowl for 2–3 minutes, until light and creamy.

Beat the egg, vanilla extract, almond extract if using, and optional food coloring into the butter mixture. Add the dry ingredients and mix only until a soft dough forms.

Divide the dough into two portions and flatten each into a disk. Wrap the disks and refrigerate for at least 30 minutes.

Heat the oven to 350°F (175°C) and line baking sheets with parchment. Roll the chilled dough to approximately 1/4-inch thickness on a lightly floured surface.

Cut out heart shapes and transfer them to the prepared baking sheets, leaving about 1 inch between cookies. Chill the cut shapes for 10–15 minutes before baking for sharper edges.

Bake for 8–11 minutes, until the edges are set and only very lightly colored. Cool the cookies on the baking sheet for 5 minutes, then transfer them to a rack to cool completely.

Whisk the confectioners' sugar, milk or water, vanilla, and optional corn syrup until smooth. Adjust the icing with tiny amounts of liquid, tint it pink or red, decorate the cooled cookies, and let the icing set before stacking.