1/3 cup semisweet chocolate chips
1 tablespoon unsalted butter or margarine
1 2/3 cups flour
1/2 cup firmly packed light brown sugar
1/4 teaspoon salt
1 tablespoon baking powder
3/4 cup milk
1/2 cup peanut butter
1/3 cup oil
1 lightly beaten egg
1 1/2 teaspoon vanilla extract
1/2 cup chopped salted peanuts without skins (optional)
Preheat oven to 400 degrees F; prepare pans.
In a small saucepan (or microwave) heat chocolate chips and butter until melted, stirring constantly; remove from heat and reserve.
In a bowl stir together flour, sugar, baking powder and salt. In an other bowl stir together milk, peanut butter, oil, egg and vanilla extract. Add dry mix to wet mix until just combined. Spoon half of batter into pans. Divide chocolate mixture among muffins, a scant teaspoon per pan; do not let filling touch sides of pan. Spoon remaining batter over filling. Sprinkle tops of muffins with chopped peanuts if desired. Bake for 20-25 minutes or until lightly browned.
Makes 9 muffins.