Beet Red Velvet Cupcakes

​In a medium saucepan, cover beets with ½-inch of water and bring to a boil, covered. Cook until very tender, about 10 minutes. Drain beets and let cool to warm.
Preheat oven to 350 degrees. Transfer beets to a food processor or blender along with milk, vinegar, and vanilla. In a separate bowl, combine flour, cocoa powder, baking powder, salt and baking soda. Beat butter with sugar and eggs. (Mixture will look broken, but it’s fine.) Combine everything.
Divide batter among buttered cupcake tins and bake until a tester comes out clean, 25-30 minutes. Let cake cool slightly, then remove from baking pans and let cool completely.
Make the frosting: Beat butter, cream cheese, sugar, vanilla and ¼ teaspoon salt together until smooth and fluffy, 2-3 minutes. Spread frosting over cupcakes and serve.

​For the cupcakes:
2 medium beets (about 10 ounces total), peeled and diced
½ cup whole milk
2 teaspoons red wine vinegar
1 teaspoon vanilla extract
1 ⅓ cups all-purpose flour
¼ cup cocoa powder
1 teaspoon baking powder
¾ teaspoon salt
½ teaspoon baking soda
½ cup (1 stick) unsalted butter, plus more for greasing pan
1 ⅓ cups sugar
2 large eggs

For the frosting:
1 cup (2 sticks) unsalted butter, at room temperature
8 ounces cream cheese, at room temperature
1 ½ cups confectioner’s sugar
2 teaspoons vanilla extract