Peanut Butter S'mores Bars

These PEANUT BUTTER S'MORES COOKIE BARS are made with a chewy, graham cracker infused peanut butter cookie base, mini marshmallows and real milk chocolate!
Course cookie
Cuisine American
Keyword cookie bars, easy desserts, party desserts, s'mores
Prep Time 15 minutes
Cook Time 25 minutes
Total Time 40 minutes
Servings 24 squares
Calories 273kcal
Author Sam Merritt


  • 1 cup unsalted butter softened (227g)
  • 1 cup creamy peanut butter I don't recommend using natural peanut butter (235g)
  • 1 cup light or dark brown sugar tightly packed (200g)
  • 1 cup granulated sugar 200g
  • 1 large egg + 1 large egg yolk
  • 1 1/2 teaspoons vanilla extract
  • 2 3/4 cups all-purpose flour 345g
  • 1/2 cup graham cracker crumbs 65g
  • 1 teaspoon baking powder
  • 1 teaspoon cornstarch
  • 1/2 teaspoon salt
  • 2 Tablespoons milk
  • 4 1.55 oz milk chocolate Hershey bars chopped into pieces*
  • 1 ½ cups mini marshmallows 72g


  • Preheat oven to 350F (175C) and line a 13x9 metal pan with parchment paper or grease and flour the sides and bottom of the pan.
  • Combine butter, peanut butter, and sugar in a large bowl and use an electric mixer to beat until light, creamy and well-combined.
  • Add egg/egg yolk and vanilla extract, and stir well.
  • In a separate bowl, whisk together flour, graham cracker crumbs, baking powder, cornstarch, and salt.
  • Gradually, on low speed, add flour mixture to peanut butter mixture, pausing occasionally to scrape down sides of bowl.
  • Add milk and stir until combined.
  • Fold in chopped Hershey bars and mini marshmallows -- the batter will be thick (I broke a spatula stirring it so proceed with caution!).
  • Spread batter into prepared ban and bake on 350F (175C) for 25-28 minutes (toothpick inserted in center should come back mostly clean with only a few crumbs)
  • Allow to cool completely before cutting and serving.


*I usually stir 3 of the hershey bars into the batter and reserve one to press on top of the cookie dough once I've spread it into the pan -- I think it makes the bars look prettier but you can just throw them in the batter if you prefer!


Serving: 1square | Calories: 273kcal | Carbohydrates: 35g | Protein: 5g | Fat: 14g | Saturated Fat: 6g | Cholesterol: 29mg | Sodium: 117mg | Potassium: 121mg | Fiber: 1g | Sugar: 21g | Vitamin A: 247IU | Calcium: 28mg | Iron: 1mg