Peanut Butter Chocolate Chip Muffin Recipe

2/3 cup peanut butter, chunky or smooth
2 tbsp. butter, melted
3/4 cup sugar
2 eggs
1-1/2 teaspoons vanilla extract
1-1/2 cups flour
1-1/2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 cup milk
6 oz. semisweet chocolate chips

1. Preheat oven to 350 degrees F.
   
2. In a large mixing bowl, combine peanut butter and melted butter; stir until well blended. Mix in sugar, eggs, and vanilla.
   
3. Combine flour with baking powder and baking soda. Add to peanut butter mixture along with milk and chocolate chips. Stir just until combined.
   
4. Spoon batter into 12 paper-lined 2 1/2- to 3-inch muffin cups. Bake 20 to 25 mins, or until muffins spring back when lightly touched in center.