Prepare the Batter: Preheat your oven to 350°F (175°C) and line a cupcake tray with paper liners. In one bowl, whisk together the flour, baking powder, baking soda, and salt. Set this aside for later.
Cream the Butter and Sugar: In a separate large bowl, cream the softened butter and granulated sugar together until the mixture is light and fluffy. This process is key to ensuring airy cupcakes!
Add the Eggs: Incorporate the eggs one at a time, making sure to mix well after each addition. Stir in the vanilla extract to give your cupcakes an extra layer of flavor.
Mix Wet and Dry Ingredients: Alternately add the buttermilk and the dry ingredients to the butter mixture, starting and ending with the dry ingredients. Be careful not to overmix; we want a tender cupcake!
Create the Red Velvet Swirl: In a small bowl, mix the cocoa powder, red food coloring, and vinegar together to form a paste. Take half of the vanilla batter and combine it with this delicious red mixture.
Layer the Batters: Drop spoonfuls of both batters into the cupcake liners, alternating colors for a beautiful marbled effect. Use a toothpick or skewer to gently swirl the batters together.
Bake the Cupcakes: Bake your cupcakes in the preheated oven for 18-20 minutes, or until a toothpick inserted in the center comes out clean. Allow them to cool completely on a rack.
Make the Frosting: In a bowl, beat the softened cream cheese and butter together until smooth. Gradually add powdered sugar and mix until fluffy; blend in vanilla extract.
Frost the Cupcakes: Once the cupcakes are completely cooled, pipe the cream cheese frosting onto each one using a decorating tip.
Add the Drizzle: Finish off by drizzling raspberry sauce or red velvet syrup over the frosted cupcakes for a show-stopping presentation!