Preheat oven to 400°F and lightly coat a muffin tin with baking spray, or line with paper liners.

In a large bowl, mix together flour, baking powder, and salt. Set aside.

In another bowl, cream together peanut butter and sugar. Beat in eggs, milk, bananas, and vanilla extract.

Pour the wet ingredients into the flour mixture and stir until mixed, but do not overmix. It should be slightly lumpy and somewhat thick. Fold in milk chocolate chips.

Divide the batter among the muffin cups, filling them to 3/4 capacity for tall, domed muffins.

Bake for 18 minutes, until a toothpick inserted in the center is clean and muffins are golden brown. Let cool slightly.

Melt peanut butter chips in the microwave, using 20-second intervals, until completely melted and stirred smooth.

Using a spoon, drizzle melted chips over the tops of the muffins. Let harden and serve.