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Flourless Peanut Butter-Chocolate Chip Oat Bars

An entire half sheet pan full of peanut butter-oat bars loaded with chocolate chips and topped with Reese's Pieces.
Course Snack
Cuisine American
Prep 10 minutes
Cook 17 minutes
Total 30 minutes
Servings 36 bars
Calories 289 kcal
Author Michelle


  • cup salted butter at room temperature
  • 2 cups light brown sugar
  • 1⅓ cups granulated sugar
  • 4 eggs
  • 1 teaspoon vanilla extract
  • teaspoons baking soda
  • 2 cups crunchy peanut butter creamy peanut butter is fine, too
  • 6 cups old-fashioned oats NOT quick-cooking oats
  • 1 cup semisweet chocolate chips
  • ½ cup Reese's Pieces


  1. Preheat oven to 350 degrees F. Lightly grease a 13x18-inch half sheet pan.
  2. With an electric mixer, beat the butter and both sugars together on medium speed until light and fluffy, about 3 minutes. Scrape down the sides of the bowl and add the eggs, one at a time, beating well after each addition. Add the vanilla extract and baking soda and beat to combine.
  3. Using a rubber spatula, stir in the peanut butter until completely combined, then stir in the oats, then the chocolate chips until all of the ingredients are fully mixed together.
  4. Turn the dough out onto the prepared baking sheet and, using your hands, press into an even layer (the dough may be slightly sticky, in which case you can dampen your hands to keep it from sticking). Sprinkle the Reese's Pieces on top and gently press into the dough.
  5. Bake until the bars are just lightly browned and no longer look wet on top, 15 to 17 minutes. Remove from the oven and allow to cool completely before cutting into bars. These can be stored in an airtight container, at room temperature, for up to 1 week.

Recipe Notes

Note: If you do not have a 13x18-inch pan and want to use a 9x13, cut all of the ingredients in half. You may need to start checking for doneness a few minutes early.

Nutritional values are based on one serving

Nutrition Facts
Flourless Peanut Butter-Chocolate Chip Oat Bars
Amount Per Serving
Calories 289 Calories from Fat 126
% Daily Value*
Fat 14g22%
Saturated Fat 5g31%
Cholesterol 27mg9%
Sodium 158mg7%
Potassium 203mg6%
Carbohydrates 35g12%
Fiber 2g8%
Sugar 23g26%
Protein 6g12%
Vitamin A 135IU3%
Calcium 32mg3%
Iron 1.4mg8%
* Percent Daily Values are based on a 2000 calorie diet.