Ingredients
Method
Preparation
- Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners and set it aside.
- In a medium bowl, whisk together the all-purpose flour, fine salt, baking powder, and baking soda.
- In a stand mixer fitted with a paddle attachment, cream together the softened unsalted butter and sugar on medium-high speed until light and fluffy, about 3 minutes.
- Add the eggs one at a time, beating well after each addition. Mix in the sour cream and vanilla extract until fully combined.
- Gradually alternate mixing in the dry ingredients and 2/3 cup of buttermilk in three batches, starting and finishing with the dry ingredients.
- Scoop out 1 cup of the batter and combine it with the cocoa powder and remaining 2 tablespoons of buttermilk. Color half of this chocolate batter with red food coloring and the other half with blue.
- Fill the cupcake liners with a teaspoon of red batter, followed by blue, and then a tablespoon of white batter on top. Repeat until the liners are about 2/3 full.
- Gently tap down the batter and use a toothpick to swirl the batters together slightly to create a marbled effect.
Baking
- Place the muffin tin in the preheated oven and bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
- Let the cupcakes cool in the pan for 5 minutes before transferring them to a cooling rack to cool completely.
Buttercream Preparation
- Place the softened salted butter in the bowl of a stand mixer and mix on medium speed until smooth.
- Add all of the sifted powdered sugar and mix on low until it turns into a powdery mixture.
- Scrape down the sides, then mix again, increasing the speed to high. Add the vanilla extract and boiling water, mixing until well combined and fluffy.
Decoration
- Transfer the buttercream into a piping bag and decorate the cooled cupcakes as you wish, adding extra flair with sprinkles or edible decorations.
Notes
Make sure your ingredients are at room temperature for best results. Use gel food coloring for more vibrant colors. Don’t open the oven door too early to prevent collapsing. Allow the cupcakes to cool completely before frosting.
