Step 1

Preheat the oven to 350 degrees F. Line 48 mini muffin cups (2 large tins or 4 small) with paper liners.

Step 2

Whisk together the flour, cocoa and 1/4 teaspoon of the salt in a medium bowl. Beat together the oil and granulated sugar on medium-high speed with a hand mixer in a large bowl until well combined. Add the egg and beat until well blended. Beat in the food coloring and 1/2 teaspoon of the vanilla.

Step 3

On low speed, alternately add the flour mixture and buttermilk in thirds, beginning and ending with the flour, beating well after each addition. Whisk together the baking soda and vinegar in a small bowl, and then beat into the batter until fully incorporated.

Step 4

Using a small ice cream scoop sprayed with nonstick cooking spray, evenly divide the batter among the cupcake liners. Bake until a toothpick inserted in the center of a cupcake comes out clean, 18 to 20 minutes. Remove the cupcakes from the tins and cool completely on a wire rack.

Step 5

Meanwhile, beat the cream cheese in a large bowl until smooth and fluffy. Sift the confectioners' sugar over the mixture and beat until smooth. Beat in the remaining 1/4 teaspoon salt and 1/2 teaspoon vanilla. Spread or pipe the frosting over the cooled cupcakes.