In a large bowl, whisk together flour, baking powder, and salt. In another large bowl using a hand mixer, beat butter and sugar until fluffy and pale in color. Add egg, milk, and vanilla and beat until combined, then add flour mixture gradually until totally combined.

Shape into 2 flattened discs and wrap in plastic. Refrigerate for 1 hour.

When ready to roll, preheat oven to 350?F and line two baking sheets with parchment paper. Lightly flour a clean work surface and roll out dough until 1/8? thick. Cut out shapes with a 2 1/2" heart-shaped cookie cutter and transfer to prepared baking sheets. Freeze for 10 minutes.

Bake until edges are lightly golden, about 8 to 10 minutes.

Make frosting: In a large bowl using a hand mixer, beat cream cheese and butter together until smooth. Add powdered sugar, vanilla, and salt and beat until combined.

Divide frosting into 3 bowls. Add pink food coloring to one bowl and red food coloring to another. Stir each bowl and add more food coloring until desired color is reached. Frost cookies using an offset spatula with each color of frosting, then top with sprinkles.