(adapted from Dorie's Chocolate Chocolate-Chunk Muffins)
6 Tbsp. unsalted butter
4 oz. bittersweet chocolate, coarsely chopped
2 c. all purpose flour
2/3 c. sugar
1/3 c. cocoa powder, sifted
1 Tbsp. baking powder
1/2 tsp. baking soda
1/2 tsp. salt
1 1/4 c. buttermilk
1 large egg
1 tsp. pure vanilla extract
Center a rack in the oven and preheat oven to 375 F. Butter or spray a 12- slot muffin pan, or line with muffin liners. Place pan on a baking sheet.
Melt butter and half the chopped chocolate in a bowl over simmering water (or in the microwave). Take off heat and set aside.
In a large bowl, mix together the flour, sugar, cocoa, baking powder, baking soda, and salt. In another bowl, whisk the buttermilk, egg, and vanilla together until well combined.
Pour the buttermilk mixture and the chocolate mixture into the dry ingredients. Mix gently but quickly to blend, but do not over mix as this will toughen the muffins. A few lumps are OK! Carefully stir in the remaining chopped chocolate and cherries.
Divide batter among the muffin tins. Bake for 20 minutes, or until a thin skewer inserted into the middle of a muffin comes out clean. Cool pan on a rack for 5 minutes before removing muffins from pan.