Chocolate Peanut Butter Mini Muffins

I tried this recipe recently and ended up making 3 batches in two days because they were such a hit. Is there really any better combination than chocolate and peanut butter?

Chocolate Peanut Butter Mini Muffins

1-3/4 cup all-purpose flour
2/3 cup packed brown sugar
2-1/2 tsp baking powder
1/4 tsp salt
1 egg
3/4 cup milk
2/3 cup peanut butter (smooth or chunky)
1/4 cup canola oil
1-1/2 tsp vanilla extract
2/3 cup miniature chocolate chips

In a large bowl, combine the flour, brown sugar, baking powder and salt. In another bowl, combine the egg,milk,peanut butter,oil, and vanilla. Beat wet mixture with an electric mixer until well combined and smooth. Stir in dry ingredients just until moistened. Fold in chocolate chips.
Fill greased or paper-lined miniature muffin cups two thirds full. Bake at 350 degrees for 15-17 minutes. Do not over bake. Check muffins about half way through baking time by inserting a toothpick in the center of one. If it comes out clean, they are done. Remove from pans and cool on a wire rack.
You can also make 12 regular size muffins with this recipe. Bake 22-25 minutes. remember, over-baking causes dry muffins. Better to take them out of the oven when they are very slightly under-baked and let the residual heat from the pan finish them.