In a bowl beat sugar, butter,milk,vanilla and egg until well blended. Add flour, baking powder and salt until dry ingredients mixed with liquid ingredients properly.
Divide dough in half. Cover one half with a plastic wrap and with another half mix red color until desired pink color, Cover it too with a plastic wrap and refrigerate both at least 2 hours.
Heat oven to 400 F. On lightly floured work surface roll out white dough with rolling pin. Cut out with 2 inch heart shaped cookie cutter. Place 1 inch apart on cookie sheets. Repeat with pink dough.
Bake 5 minutes and then cool down for a while and removed from cookie sheets.