1/2 cup unsalted butter (1 stick), melted
1 large egg
1 cup light brown sugar, packed
1 tablespoon vanilla extract
heaping 1/2 cup creamy peanut butter (use Jif, Skippy, etc.; don’t use homemade or natural – too runny)
1 cup all-purpose flour
1 cup Peanut Butter M&Ms (or Peanut, Plain, or favorite variety)
3/4 cup semi-sweet chocolate chips or chunks, or a combination
1/2 cup Reese’s Peanut Butter Chips
1/3 cup Heath Bar Toffee Bits
- Preheat oven to 350F. Line an 8-by-8-inch baking pan with aluminum foil, spray with cooking spray; set aside.
- In a large, microwave-safe bowl melt the butter, about 1 minute on high power.
- Wait momentarily before adding the egg so you don’t scramble it. Add the egg, brown sugar, vanilla, and whisk until smooth.
- Add the peanut butter and whisk or stir until smooth and incorporated.
- Add the flour and stir until just combined, don’t overmix.
- Add all remaining add-ins and fold to incorporate.
- Turn batter out into prepared pan, smoothing the top lightly with a spatula. I like to strategically place a few M&Ms on the top of the batter for a nice visual effect.
- Bake for about 25 minutes, or until top is set. 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. Bars will keep airtight at room temperature for up to 1 week, or in the freezer for up to 6 months.