1 ½ cups pomegranate juice
1 cup (225g) granulated sugar
¾ cup (170g) soft unsalted butter or margarine
2 large eggs
¾ cups buttermilk or soy milk
1 tablespoon white vinegar
1 teaspoon vanilla extract
1 ¾ cup flour
2 ½ tablespoons cocoa powder
2 teaspoons baking soda
1 cup pomegranate juice
¼ cup flour
1 cup (2 sticks) unsalted butter or margarine, softened
1 cup sugar
For the cake: Cook the pomegranate juice down, over low heat, until it is reduced by about half. Set aside.
Beat the butter and sugar together until light and fluffy. Add the eggs, one at a time, and beat to combine. Add in the buttermilk slowly and mix until smooth. Add the vanilla, vinegar, flour, cocoa powder, baking soda and salt, and mix until everything is just combined.
Divide the mixture up among 12-16 paper-lined muffin tins. Bake at 350 F for 20 to 25 minutes. Let cool in the pan for five minutes, then remove them to a wire rack to finish cooling completely.
For the icing: use a small saucepan to bring the pomegranate juice and flour to a low simmer. Cook, stirring constantly, for about five minutes until thickened. Chill the mixture in the fridge until completely cold.
Beat the butter and sugar together, at least five minutes, until light and fluffy. Mix in the pomegranate juice and flour mixture until evenly dispersed. Use to cover cupcakes.