Chocolate Peanut Butter Swirl Muffins

INGREDIENTS

For the muffins:

6 tbsp

unsalted butter, at room temperature

2/3 cup

semisweet chocolate chips, divided

2 cups

all-purpose flour

2/3 cup

sugar

1/3 cup

unsweetened cocoa powder

1 tbsp

baking powder

1/2 tsp

baking soda

1/2 tsp

salt

1 1/4 cups

buttermilk

large egg

2 tsp

vanilla extract

For the peanut butter swirl:

1/3 cup

creamy peanut butter

1 tbsp

unsalted butter, melted

1/2 cup

confectioners’ sugar

1 tbsp

milk