01 - Preheat your oven to 350°F. Line a 12-cup muffin tin with cupcake liners.
02 - In a medium mixing bowl, whisk together the all-purpose flour, baking powder, and salt. Set aside.
03 - In a large mixing bowl, using an electric mixer, beat the softened unsalted butter and granulated sugar together until the mixture is light and fluffy, approximately 2 to 3 minutes.
04 - Add the large eggs one at a time, beating thoroughly after each addition until fully incorporated. Stir in the vanilla extract.
05 - With the mixer on low speed, alternately add the prepared flour mixture and the sparkling pink grape juice to the butter mixture, beginning and ending with the flour. Mix until just combined, being careful not to overmix. If desired, incorporate 2 to 3 drops of pink food coloring.
06 - Evenly divide the cupcake batter among the lined muffin cups, filling each approximately two-thirds full.
07 - Bake for 18 to 20 minutes, or until a wooden toothpick inserted into the center of a cupcake comes out clean. Allow the cupcakes to cool in the muffin pan for 5 minutes before transferring them to a wire rack to cool completely.
08 - For the frosting, beat the softened unsalted butter until creamy. Gradually add the sifted powdered sugar, mixing until well combined. Incorporate the sparkling pink grape juice, vanilla extract, pinch of salt, and 1 to 2 drops of pink food coloring (if using). Beat until the frosting is light and fluffy.
09 - Once the cupcakes have cooled completely, frost them generously with the pink grape juice frosting using a piping bag or an offset spatula. Garnish with edible glitter or sprinkles as desired.