Chocolate Cupcakes with Fluffy Marshmallow Buttercream

Ingredients

1 1/2 cups all-purpose flour

1 cup granulated sugar

3/4 cup cocoa powder

1 teaspoon baking soda

1/2 teaspoon baking powder

1/2 teaspoon salt

2 large eggs, at room temperature

1/2 cup vegetable oil

1 cup buttermilk, at room temperature

2 teaspoons pure vanilla extract

For the Marshmallow Buttercream:

3 sticks unsalted butter, softened to room temperature

6 cups confectioners’ sugar, sifted if lumpy

3 tablespoons heavy cream or milk, plus more as needed for desired consistency

7 ounces marshmallow fluff