In a large bowl, cream together the butter and sugar until light and fluffy. Beat in eggs one at a time, then stir in vanilla. Combine the flour, baking powder, and salt; gradually stir into the creamed mixture. Divide dough into two parts, wrap in plastic, and refrigerate for 1 hour.

Preheat oven to 350°F (175°C). On a lightly floured surface, roll out dough to 1/4 inch thickness. Cut into shapes with a heart-shaped cookie cutter. Place cookies 1 inch apart on ungreased baking sheets.

Bake for 10 to 12 minutes in preheated oven, or until edges are lightly browned. Remove from baking sheets to cool on wire racks.

In a medium bowl, mix together the powdered sugar, milk, and vanilla extract until smooth. Add food coloring until desired shade of pink is achieved.

Once cookies are completely cool, use a piping bag or a small spoon to apply icing to the cookies. Allow icing to set completely before serving or storing.

Arrange cookies on a platter and serve with tea or coffee for a delightful Valentine's Day treat.

Store decorated cookies in an airtight container at room temperature for up to a week. For longer storage, freeze undecorated cookies and icing separately.