1-First Step: Preheat and Prep Preheat your oven to 350°F and grease an 8×8-inch baking pan or line with parchment paper. This prevents sticking and makes slicing easy. Gather all ingredients at room temperature for smooth mixing; cold items lead to lumps.

2-Second Step: Melt Chocolate and Butter In a microwave-safe bowl, combine 1/2 cup unsalted butter and 4 oz unsweetened chocolate. Microwave in 30-second bursts, stirring between each, until fully melted and smooth, about 1-2 minutes total. Let cool slightly to avoid cooking eggs later. This base creates the fudgy heart of your chewy peanut butter pieces brownies.

3-Third Step: Mix Wet Ingredients In a separate large bowl, whisk 1 cup granulated sugar, 2 large eggs, and 1/4 cup creamy peanut butter until light and creamy, about 2 minutes. The mixture should ribbon off the whisk. Add 1 tsp vanilla if using for extra depth. This step builds emulsification for even texture.

4-Fourth Step: Combine Wet and Chocolate Mixtures Pour the cooled chocolate-butter mix into the egg-sugar bowl. Stir gently until uniform. Avoid overmixing here to keep air in for chewiness. The batter turns glossy and thick.

5-Fifth Step: Add Dry Ingredients and Candy Sift in 2/3 cup all-purpose flour and 1/4 tsp salt. Fold just until no streaks remain, about 10 strokes. Stir in 3/4 cup Reese’s Pieces candy. Spoon batter into pan, spread evenly, and press remaining 1/4 cup candy on top. This topping adds visual pop and extra chew.

6-Sixth Step: Bake Bake at 350°F for 25-30 minutes. Edges set firm, but center stays fudgy with a slight jiggle for ultimate chewy brownies. Overbaking dries them out; start checking at 25 minutes with a toothpick it should come out with moist crumbs.

7-Final Step: Cool and Serve Cool in pan on a wire rack for 1 hour, then refrigerate 30 minutes for clean cuts. Slice into 16 squares. Serve at room temp or warm. Pair with milk or top with [chocolate buttercream frosting](https://cookingfee.com/chocolate-buttercream-frosting/) for decadence. Total yield: 16 servings, perfect for sharing.