• Preheat the oven to 350°F. Line a muffin tin with cupcake liners.
• Whisk the flour, cocoa powder, baking powder, baking soda, and salt together in a medium bowl until combined. Set aside.
  1 cup (148g) flour*, ½ cup (42g) unsweetened cocoa powder, ½ teaspoon baking powder, ½ teaspoon baking soda, ¼ teaspoon fine salt
• Using a hand mixer or a stand mixer fitted with the paddle attachment, beat the sugar, butter, and oil until smooth. Add the eggs and vanilla extract and beat to combine.
  ⅔ cup (134g) sugar, 4 tablespoons (57g) unsalted butter, ¼ cup (60ml) vegetable or canola oil, 2 eggs*, ½ teaspoon vanilla extract
• Add the dry ingredients in thirds, alternating with the milk and making sure to start and end with dry ingredients. Beat between each addition to incorporate.
  ½ cup (120ml) milk of choice
• Spoon the batter into the cupcake liners, a little over halfway full. Bake for 18-20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Cool completely before frosting.

Buttercream Frosting

• To make the frosting, use a hand mixer or a stand mixer fitted with the paddle attachment to beat the butter until smooth and creamy, about 4-5 minutes. Add the powdered sugar and beat until combined, another 3-4 minutes. Add the heavy cream, one tablespoon at a time, until you have the desired consistency.
  1 ½ cups (340g) unsalted butter, 4 ½ cups (540g) powdered sugar, 2-4 tablespoons heavy cream
• Separate the frosting into thirds. Leave one third white and use gel food coloring to tint the second portion yellow and the third portion orange. Transfer to three separate piping bags and pipe a swirl of yellow, followed by a slightly smaller swirl of orange on top, and an even smaller swirl of white on top of that. Repeat with all cupcakes.
  orange and yellow gel food coloring