Ingredients
1/2 cup (1 stick) salted butter, melted
1 cup packed light brown sugar
1 egg
2 teaspoons vanilla extract
1 cup all-purpose flour
1 cup chocolate chips, divided
1/2 cup creamy peanut butter
Directions
Preheat oven to 350F. Create a foil sling for your 8 x 8 inch baking pan and spray with baking spray; set aside.
In a medium bowl, stir together the melted butter and brown sugar. Add the egg and vanilla and stir to combine. Add the flour and stir just until combined, taking care not to overmix. Fold in 3/4 cups chocolate chips. Pour batter into the prepared pan, smoothing with an offset spatula if needed.
Melt the peanut butter in the microwave for about 45 seconds, on high power, and stir until smooth. Evenly drizzle the peanut butter over the batter. Run a knife through the batter, back and forth a few times, to marble it. Sprinkle the remaining 1/4 cup chocolate chips over the top.
Bake for 25 to 28 minutes, or until the edges begin to slightly pull away from the pan. The peanut butter won’t appear fully done but will set up as the blondies cool.
Allow the bars to cool for at least 30 minutes before slicing and serving.