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 colour. Add egg, milk, and vanilla and beat until combined, then add flour mixture gradually until totally combined.
Shape into a disk and wrap in plastic. Refrigerate 1 hour.
When ready to roll, heat up your Cobb cooker and line two baking sheets (that fits the Cobb) with parchment paper. Lightly flour a clean work surface and roll out dough until 1/8” thick. Using a heart shaped cookie cutter, cut out cookies and transfer to prepared baking sheets.
Bake until edges are lightly golden, 8 to 10 minutes.
Make frosting: In a large bow 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 colouring to one bowl and red food colouring to another. Stir each bowl and add more food colouring until desired colour is reached.
Frost cookies using an offset spatula with each colour of frosting, then top with sprinkles.