Preheat oven to 350 degrees F (175 degrees C) and line 12 muffin tins (for large cupcakes) or 15 muffin tins (for regular sized cupcakes) with paper cupcake liners.

In a large bowl sift together the flour, salt, and cocoa powder.

In the bowl of your electric mixer, or with a hand mixer, beat the butter until soft (about 1-2 minutes). Add the sugar and beat until light and fluffy (about 2-3 minutes). Add the eggs, one at a time, beating well after each addition. Scrape down the sides of the bowl. Add the vanilla extract and beat until combined.

In a measuring cup whisk the buttermilk with the red food coloring. With the mixer on low speed, alternately add the flour mixture and buttermilk to the butter mixture, in three additions, beginning and ending with the flour.

In a small cup combine the vinegar and baking soda. Allow the mixture to fizz and then quickly fold into the cake batter. 

Working quickly, divide the batter evenly between the 12 (or 15) muffin tins and smooth the tops with an offset spatula or the back of a spoon. Bake in the preheated oven for approximately 20 - 25 minutes, or until a toothpick inserted in the center of the cakes comes out clean.

Cool the cakes in their pans on a wire rack for 10 minutes and them remove from pan. Let cool completely before frosting. Either spread the frosting with a knife or offset spatula, or use a large 1M Wilton open star decorating tip to pipe the frosting.

Cream Cheese Frosting: In the bowl of your electric mixer, or with a hand mixer, beat the cream cheese and mascarpone cheese until smooth. Add the vanilla and confectioners sugar and beat until smooth.

Then, in another bowl of your electric mixer, or with a hand mixer, whip the heavy cream until soft peaks form. With a large spatula, gently but quickly fold a little of the whipped cream into the cream cheese mixture to lighten it. Then fold in the remaining whipped cream, in two stages. If the frosting is not thick enough to pipe, cover and place in the refrigerator until firm.

Makes 12 large cupcakes.

Note: If you want regular sized cupcakes, only fill the muffin tins about 2/3 full. This will give you about 15 regular sized muffins.