Reeses Peanut Butter Oatmeal Cookie Bars
If you’re a fan of the irresistible combination of peanut butter and chocolate, then you are in for a delightful treat with these Reeses Peanut Butter Oatmeal Cookie Bars. Imagine soft, chewy bars filled with creamy peanut butter and loaded with chunks of Reese’s chocolate candies. They are perfect for any occasion, whether you’re hosting a gathering or just having a cozy night in with a movie. These bars are not only easy to make, but they also come together quickly, ensuring that sweet cravings are satisfied in no time!
Why You’ll Love This Recipe

These Reeses Peanut Butter Oatmeal Cookie Bars are the ultimate indulgence. The buttery, soft texture combined with the hearty oats creates a perfect base for the sweet and salty flavors of peanut butter and chocolate. Plus, they are incredibly versatile—you can enjoy them warm right out of the oven or let them cool for a sweet snack on the go. With minimal effort and maximum flavor, these bars will quickly become a favorite in your household.
What Goes In
To whip up these delicious Reeses Peanut Butter Oatmeal Cookie Bars, you will need the following ingredients:
- 1 1/2 sticks unsalted butter, softened
- 2 cups light brown sugar
- 1/2 cup creamy peanut butter
- 2 eggs, room temperature
- 1 tbsp vanilla extract
- 2 cups all-purpose flour
- 1 cup old-fashioned oats
- 2 1/2 tsp baking powder
- 1/4 tsp salt
- 1 cup Reese’s peanut butter baking chips
- 2 cups Reese’s miniatures, chopped or Reese’s minis
Prep & Cook Tools
To create these delightful bars, gather the following tools:
- Mixing bowls – For combining your ingredients.
- Whisk or electric mixer – To beat the butter and sugars together.
- Spatula – For folding in the oats and chocolate pieces.
- 9×13-inch baking pan – The perfect size for these bars.
- Parchment paper – Optional, for easy removal from the pan.
- Oven – Preheated to ensure even baking.
Reeses Peanut Butter Oatmeal Cookie Bars Made Stepwise

Step 1: Preheat the Oven
Preheat your oven to 350°F (175°C). This step is crucial for ensuring that your cookie bars bake evenly.
Step 2: Prepare the Baking Pan
Grease a 9×13-inch baking pan or line it with parchment paper. This will help you easily lift out the bars once they are baked.
Step 3: Cream the Butter and Sugars
In a large mixing bowl, combine the softened unsalted butter and light brown sugar. Use an electric mixer or a whisk to cream them together until the mixture is light and fluffy.
Step 4: Add Peanut Butter, Eggs, and Vanilla
Mix in the creamy peanut butter until well combined. Then, add the room temperature eggs one at a time, followed by the vanilla extract. Be sure to mix thoroughly after each addition.
Step 5: Combine Dry Ingredients
In a separate bowl, whisk together the all-purpose flour, old-fashioned oats, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, stirring until just combined. Avoid overmixing to keep the bars tender.
Step 6: Fold in the Chocolate
Gently fold in the Reese’s peanut butter baking chips and chopped Reese’s miniatures until evenly distributed throughout the dough.
Step 7: Spread the Batter
Pour the cookie batter into the prepared baking pan, spreading it evenly with a spatula. Make sure to smooth the top for an even bake.
Step 8: Bake
Place the baking pan in the preheated oven and bake for 25-30 minutes, or until the edges are golden and a toothpick inserted in the center comes out with a few moist crumbs.
Step 9: Cool and Cut
Once baked, remove the pan from the oven and allow the bars to cool in the pan for about 15 minutes. Then, transfer them to a wire rack to cool completely before cutting them into squares.
Warm & Cool Weather Spins

These Reeses Peanut Butter Oatmeal Cookie Bars are delightful year-round, but you can add a twist based on the season:
- Warm Weather: Serve them chilled with a scoop of vanilla ice cream on top for a refreshing treat.
- Cool Weather: Drizzle with melted chocolate and sprinkle with sea salt for an extra indulgent dessert.
- Fall: Add a pinch of cinnamon or nutmeg to the batter for a warm, cozy flavor.
- Winter: Mix in some crushed peppermint candies for a festive touch during the holidays.
Chef’s Notes
- Ensure that your butter is softened but not melted for the best texture.
- For a nutty flavor, consider adding chopped nuts like peanuts or almonds to the batter.
- If you prefer a thicker bar, you can use a smaller baking pan, but adjust the baking time accordingly.
- Feel free to experiment with different types of chocolate chips or candies to customize your bars.
How to Store & Reheat
To keep your Reeses Peanut Butter Oatmeal Cookie Bars fresh, follow these storage tips:
- Store the bars in an airtight container at room temperature for up to 5 days.
- For longer storage, you can freeze the bars. Wrap them tightly in plastic wrap and place them in a freezer-safe container. They will last for up to 3 months.
- To reheat, simply microwave a bar for 10-15 seconds or warm them in the oven at 350°F for about 5 minutes.
Troubleshooting Q&A
Why are my cookie bars too dry?
Overbaking can lead to dry bars. Make sure to check them a few minutes before the recommended baking time, as ovens can vary.
What if my bars are too crumbly?
Ensure you’re measuring the flour correctly. Too much flour can make the bars crumbly. Use the spoon-and-level method for accurate measurement.
Can I use natural peanut butter instead?
Yes, but be aware that natural peanut butter can alter the texture slightly, making the bars a bit denser. Stir the natural peanut butter well before measuring.
How can I add more chocolate flavor?
In addition to the Reese’s pieces, you can mix in dark or milk chocolate chips for an extra chocolatey experience.
Make It Tonight
Now that you have the perfect recipe for Reeses Peanut Butter Oatmeal Cookie Bars, it’s time to gather your ingredients and start baking! These bars are sure to impress everyone who gets a taste. Whether you’re treating yourself or sharing with friends and family, they are bound to be a hit. So roll up your sleeves, get ready to mix, and enjoy the deliciousness that awaits!
The moment you pull these bars from the oven, the warm, sweet aroma of peanut butter and chocolate will fill your kitchen, creating the perfect atmosphere for a cozy baking experience. Slice, serve, and watch as they disappear in no time. Happy baking!

Reeses Peanut Butter Oatmeal Cookie Bars
Ingredients
Equipment
Method
- Preheat your oven to 350°F (175°C).
- Grease a 9x13-inch baking pan or line it with parchment paper.
- In a large mixing bowl, combine softened unsalted butter and light brown sugar. Cream them together until light and fluffy.
- Mix in the creamy peanut butter, then add the eggs one at a time, followed by the vanilla extract.
- In a separate bowl, whisk together flour, oats, baking powder, and salt. Gradually add to the wet ingredients, stirring until just combined.
- Fold in the Reese's peanut butter baking chips and chopped Reese's miniatures.
- Pour the batter into the prepared baking pan, smoothing the top.
- Bake for 25-30 minutes or until the edges are golden and a toothpick comes out with a few moist crumbs.
- Cool in the pan for about 15 minutes, then transfer to a wire rack to cool completely before cutting into squares.
Notes
- Ensure butter is softened but not melted for the best texture.
- Consider adding chopped nuts for extra flavor.
- For thicker bars, use a smaller baking pan and adjust baking time.
