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Stack of three peanut butter blondies, one on top of each other
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4.67 from 6 votes

Peanut Butter Blondies

These peanut butter blondies are soft and chewy with a delicious peanut butter flavor and tons of Reese's Pieces and chocolate chips. A quick, easy, one-bowl, no mixer recipe.
Prep Time10 minutes
Cook Time27 minutes
Total Time40 minutes
Course: Dessert
Cuisine: American
Keyword: Peanut Butter Blondies
Servings: 15 large blondies
Author: Fiona Dowling

Equipment

  • 9x13 inch (23 x 33 cm) baking pan* see Notes for alternatives

Ingredients

  • 2/3 cup unsalted butter (170 grams)
  • 3/4 cup peanut butter (about 270 grams)
  • 2 cups light brown sugar (420 grams)
  • 2 teaspoons vanilla
  • 3 large egg
  • 2 cups all-purpose flour (250 grams)
  • 1/4 teaspoon salt
  • 3/4 cup Reese's Pieces (about 140 grams)
  • 3/4 cup chocolate chips (about 120 grams)

Instructions

  • Preheat the oven to 350F (180C) degrees. 
  • Line a 9x13 inch pan with parchment leaving an overhang over the sides or lightly grease.
  • In a large, microwave-safe bowl, melt together the butter and peanut butter. When almost melted, stir together until smooth. 
  • Whisk the brown sugar into the peanut butter mixture. Then whisk in the eggs and vanilla extract until you no longer see pieces of egg.
  • Gently fold in the flour and salt into the mixture. Stop mixing when you no longer see streaks or lumps of flour.
  • Fold in the Reese's Pieces and chocolate chips.
  • Spoon/pour the batter into the prepared pan and spread the top smooth
  • Bake in the preheated oven for about 30 minutes, or until the top looks set an inserted toothpick comes out clean or with a few damp crumbs. Bake time is partially a personal preference - if you prefer bars that aren't as gooey, I recommend baking for 35 minutes.
  • Cool the bars in the pan. When ready to slice, lift the bars out of the pan with the overhang of the parchment paper (if you lined the pan). Place on a cutting board and slice with a thin, sharp knife. If you greased the pan, simply slice with a thin, sharp knife. I cooled the blondies for 2 1/2 hours before slicing and the chocolate chips and Reese's Pieces were still melty.

Notes

  1. Peanut Butter: I recommend using smooth peanut butter. Crunchy works too. I do not recommend using homemade or natural peanut butter in baking because it can lead to inconsistent results due to the peanut butter separating.
  2. Mix-Ins: Feel free to use 1 1/2 cups total of your favorite mix-ins - such as chocolate chips, peanut butter chips, Reese's Pieces or chopped peanut butter cups.
  3. For a Smaller Batch: Use an 8x8 inch (20x20 cm) pan. The bake time will be closer to 25 minutes. You'll need:
    • 1/3 cup unsalted butter
    • 1/4 cup plus 2 tablespoons peanut butter
    • 1 cup brown sugar
    • 1 teaspoon vanilla extract
    • 1 large egg plus 1 additional egg yolk 
    • 1 cup all-purpose flour
    • pinch of salt
    • 6 tablespoons Reese's Pieces
    • 6 tablespoons chocolate chips
  4. Storage: Store in an airtight container at room temperature for up to 4 days. Baked and cooled blondies can be frozen in an airtight container for up to 2 months. I recommend placing a sheet of wax paper between blondies to avoid them sticking together when freezing thaw in the fridge. 
  5. Nutrition: Details provided are an estimate only and based on 1 blondie, assuming the pan yields 15 uniform large blondies. You can likely get 18 or more smaller blondies from this recipe. 

Nutrition

Calories: 429kcal | Carbohydrates: 56g | Protein: 8g | Fat: 20g | Saturated Fat: 10g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 6g | Trans Fat: 0.4g | Cholesterol: 60mg | Sodium: 142mg | Potassium: 180mg | Fiber: 2g | Sugar: 41g | Vitamin A: 326IU | Vitamin C: 0.1mg | Calcium: 58mg | Iron: 2mg