Double Chocolate Muffins

1/2 cup unsalted butter, softened
1 cup sugar
2 teaspoons vanilla
2 teaspoons baking powder
2/3 cup unsweetened cocoa powder
1/2 teaspoon salt
2 eggs
1 cup milk (skim, 1%, 2%, whatever you have works)
1/3 cup sour cream
2 cups all-purpose flour
1 1/2 cups chocolate chips (I used mini chips)

1) Preheat oven to 350 degrees F. Line a muffin pan with paper liners to make 12 muffins.

2) Cream together the butter, sugar, sour cream, and vanilla until light and fluffy - about 3 minutes. Add the eggs, one at a time, beating until incorporated between each addition.

3) Stir together the flour, baking powder, cocoa powder, and salt. Add flour mixture to butter mixture alternately with the milk, in 2-3 additions each (so add a third of the flour, half of the milk, another third of the flour, etc.). Stir in chocolate chips.

4) Divide batter between 12 muffin cups and bake 25-27 minutes, until toothpick comes out clean (a little melted chocolate is fine - the toothpick may hit a melty chocolate chip).