Preheat the oven: Begin by preheating your oven to 350°F (175°C) and lining a muffin tin with colorful cupcake liners.
Mix wet ingredients: In a large mixing bowl, combine 4 egg whites, ½ cup vegetable oil, and 1½ cup grape soda. Whisk them together until fully blended.
Incorporate dry ingredients: Gradually add 15.25 oz white cake mix and 0.14 oz unsweetened grape drink mix into the wet ingredients. Mix until combined, then add 4-6 drops of purple gel food color and stir until the batter is uniform in color.
Fill the liners: Using a ladle or ice cream scoop, fill each cupcake liner about ⅔ full with the batter, ensuring even distribution for uniform baking.
Bake: Place the muffin tin in the preheated oven and bake for approximately 15 minutes, or until a toothpick inserted into the center comes out clean.
Cool: Remove the cupcakes from the oven and allow them to cool completely in the tin before transferring them to a wire rack.
Prepare the frosting: While the cupcakes are cooling, make the buttercream frosting. In a medium bowl, beat 1 cup softened salted butter with 2 tsp vanilla extract and ¼ tsp almond extract until the mixture is light and fluffy.
Incorporate sugar and cream: Gradually add 4 cups sifted powdered sugar, mixing at low speed to avoid a sugar cloud. Once combined, add 2-3 tbsp heavy cream and 4-6 drops purple gel food color, mixing until smooth.
Frost the cupcakes: Using a piping bag fitted with your choice of tip, pipe the frosting onto the cooled cupcakes, creating swirls or peaks as desired. For a finishing touch, sprinkle with purple sparkling sugar if using.