1. Preheat oven to 350 degrees F. Line a baking sheet with parchment paper.
2. Lightly dust a work surface with flour. Use a rolling pin to roll the pie crust into a 13-inch diameter circle. Cut 16 hearts into the pie dough using a 2 1/2-inch heart-shaped cookie cutter.
3. Use a spatula to transfer 8 of the hearts to the baking sheet. Spoon 1 tsp. jam onto the center of each of the 8 hearts. Spread the jam across the dough, leaving a 1/3-inch border. Lightly brush the boarders with milk. Transfer the remaining 8 pieces of pie dough to top the jam-covered hearts, being sure the edges line up. Use the tines of a fork to seal the edges of the dough.
4. Bake about 18 minutes or until the tarts are golden brown around the edges with the tops just beginning to brown. Remove from oven and cool completely.
5. Make the frosting in a bowl by whisking together the powdered sugar, butter, milk, and food coloring until creamy and smooth. Spread the frosting over the tarts.