Step 1

Preheat oven to 350F. Line an 8-by-8-inch baking pan with aluminum foil, spray with cooking spray; set aside.

Step 2

In a large, microwave-safe bowl melt the butter, about 1 minute on high power.

Step 3

Wait momentarily before adding the egg so you don’t scramble it. Add the peanut butter, egg, brown sugar, vanilla, and whisk until smooth.

Step 4

Add the flour and stir until just combined, don’t overmix.

Step 5

Stir in 1 cup chocolate chips.

Step 6

Turn batter out into prepared pan, smoothing the top lightly with a spatula.

Step 7

Sprinkle evenly with 2 tablespoons chocolate chips, smoothly the top lightly with a spatula.

Step 8

Bake for about 20 to 25 minutes, or until done. A toothpick inserted in the center should come out clean, or with a few moist crumbs, but no batter. Allow bars to cool in pan for at least 30 minutes before slicing and serving.

Step 9

Bars will keep airtight at room temperature for up to 1 week, or in the freezer for up to 6 months.