Preheat your oven to 350°F (175°C) and grease your 9x13 inch baking pan or line it with parchment paper for easy removal.
In a large mixing bowl, whisk together the all-purpose flour, unsweetened cocoa powder, granulated sugar, and salt.
In a separate bowl, beat the eggs and then mix in the vegetable oil. Stir well until combined.
Pour the wet mixture into the dry ingredients. Using a spatula, gently mix until just combined.
Fold in the peanut butter chips into the batter, ensuring they are evenly distributed.
Spread half of the brownie batter into the prepared baking pan.
Place the unwrapped miniature Reese’s Peanut Butter Cups evenly over the batter. Pour the remaining brownie batter on top, spreading it out to cover the Reese’s Cups.
Sprinkle the Reese’s Pieces over the top of the brownie batter for an extra crunch and visual appeal.
Bake in your preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Once baked, remove the brownies from the oven and allow them to cool in the pan on a wire rack. Once completely cool, slice them into squares and enjoy your ULTIMATE Reeses Brownies!
