Homemade Breakfast Tarts

Name: Homemade Breakfast Tarts
Ingredients: 3 cups all-purpose flour, plus more for rolling; 2 tablespoons granulated sugar; 1 teaspoon salt; 1 cup (2 sticks) cold butter, cubed; 1 egg; 5 tablespoons cold water (or more if needed); 1 tablespoon distilled vinegar; One 13-ounce jar mixed berry jam (about 1 1/4 cup); 1 egg, lightly beaten for egg wash; 1 1/4 cup powdered sugar; 2 tablespoons milk; 1 tablespoon mixed berry jam; 2 drops neon purple food coloring; Multicolored jimmies or sprinkles