Peanut Butter Sugar Cookie Bars are my go-to when I want a soft and chewy cookie bar that slices cleanly and actually stays tender the next day. They’re baked in one pan, so you get that classic cookie flavor without babysitting multiple trays.
The texture is the best part for me: thick, buttery edges with a peanut butter center that stays a little dense and chewy. And if you like a sweeter finish, the peanut butter frosting on top is simple and smooth.
I like these for cookie trays, bake sales, and lunchbox treats because they travel well and don’t crumble all over the place. They’re also a nice dessert to keep in the fridge when you want something quick to slice and serve.
Why You’ll Love This Recipe
Soft and Chewy: These stay tender in the middle, with just enough golden edge to feel like a real cookie bar.
One Pan: No scooping, no rotating cookie sheets, and no guessing if the second batch will bake the same as the first.
Big Peanut Butter Flavor: The peanut butter comes through clearly, not just as a background note.
Frosting Optional: You can keep them simple with a sugar topping, or add the peanut butter frosting for a thicker, sweeter bar.
Easy to Tweak: Crunchy peanut butter works, and chocolate chips fit right in if you want a little extra going on.
Ingredients You’ll Need
Cookie Bars
- Unsalted butter: I like starting with softened butter so it creams quickly and evenly. If it’s too melty, the dough can feel loose.
- Creamy peanut butter: Regular creamy peanut butter is what I use here (the classic jar kind). Crunchy works too if you want more texture.
- Granulated sugar: This gives that familiar sugar-cookie sweetness and helps the top set up nicely.
- Light brown sugar: Brown sugar is where a lot of the chew comes from. Dark brown sugar is fine if that’s what you have.
- Eggs: These help the bars hold together and keep the center soft.
- Vanilla extract: Don’t skip it. It makes the dough taste more like a classic cookie.
- All-purpose flour: I use regular flour here. Spoon and level if you tend to over-pack your measuring cup.
- Baking powder: Helps the bars lift a little so they don’t bake up too dense.
- Baking soda: Gives the dough a bit of spread and that cookie-bar texture instead of a cake feel.
- Fine salt: Peanut butter needs salt to taste right. If you only have salted butter, I’d still add a small pinch.
- Granulated sugar (topping): Optional, but I like it for a little crunch on top and that classic sugar-cookie look.
Peanut Butter Frosting (Optional)
- Unsalted butter: Softened butter makes the frosting smooth instead of lumpy. Give it a few minutes on the counter if it’s cold.
- Creamy peanut butter: This is what makes the frosting taste like peanut butter cup filling. Crunchy peanut butter is okay, just more textured.
- Powdered sugar: This sweetens and thickens the frosting. If it’s clumpy, sift it or whisk it first.
- Milk: Start with a little, then add more if you need it. It doesn’t take much to loosen the frosting.
- Vanilla extract: A small amount rounds out the sweetness.
- Salt: Just a pinch makes the frosting taste less flat.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F. Grease a 9×13-inch baking pan or line it with parchment paper.
- Mix the dry ingredients: Whisk the flour, baking powder, baking soda, and salt together in a medium bowl, then set aside.
- Cream the butter and sugars: Beat the butter, peanut butter, granulated sugar, and brown sugar until light and fluffy.
- Add the eggs and vanilla: Beat in the eggs, then add the vanilla and mix until smooth.
- Add the dry ingredients: Mix in the flour mixture just until combined. Stop as soon as you don’t see dry flour so the bars stay chewy.
- Press into the pan: Press the dough evenly into the prepared pan and smooth the top. Sprinkle with the topping sugar if you’re using it.
- Bake: Bake for 18 to 22 minutes, until the edges are lightly golden and the center looks set. Don’t overbake if you want chewy bars.
- Cool: Let the bars cool completely in the pan before slicing.
- Make the frosting (optional): Beat the butter and peanut butter until creamy. Mix in powdered sugar, vanilla, salt, and milk until smooth and spreadable.
- Frost and slice: Spread the frosting over the cooled bars, then chill briefly if you want cleaner cuts. Slice into bars and serve.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Don’t overbake the pan. Pull the bars when the edges look lightly golden and the center looks set. They’ll keep baking a little from the heat in the pan.
Use parchment if you can. It makes it much easier to lift the whole slab out for neater frosting and cleaner slices.
Stop mixing once the flour is in. Overmixing makes cookie bars tougher. Mix just until you don’t see dry streaks.
Try crunchy peanut butter if you like texture. It works the same way in the dough, and you get little crunchy bits throughout.
Go smaller on the bake time if they seem dry. If your oven runs hot, shaving off 2 minutes can make a big difference. Let them cool fully before deciding they’re overdone.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Milk: A cold glass of milk is classic with peanut butter bars. It’s especially nice if you frost them.
- Coffee: These are great with coffee, especially something simple like drip coffee or an americano. The peanut butter flavor really comes through.
- Ice cream: Serve a bar with vanilla ice cream on the side if you want a more “dessert-dessert” plate. A little chocolate sauce is good too.
- Fruit: Fresh strawberries or banana slices are nice with peanut butter. It keeps the plate from feeling too heavy.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store the bars covered at room temperature for 2 to 3 days if they’re unfrosted. If your kitchen is warm, I still usually move them to the fridge just so they stay firm and easy to slice.
For frosted bars, store leftovers covered in the fridge for up to 4 days. Let them sit out for 10 to 15 minutes before serving if you want the frosting softer.
You can make this recipe ahead by baking the bars a day early and frosting them the next day. I like doing it that way because the bars are fully cooled and the frosting spreads more neatly.
If you want them to last longer, freeze individual portions in an airtight container. Thaw in the fridge overnight or on the counter for about an hour.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
Can I use crunchy peanut butter?
Yes. Crunchy peanut butter works fine in both the bars and the frosting. The bars will just have a little more texture.
How do I know when the bars are done?
I look for lightly golden edges and a center that looks set, not jiggly. If you wait until the whole pan looks deeply browned, they can end up dry once they cool.
Can I add chocolate chips?
You can. I like mixing in up to 1/2 cup chocolate chips for a chocolate-and-peanut-butter situation without turning them into full-on chocolate chip bars.
Can I bake these in a 9×9-inch pan?
Yes, for thicker bars. The bake time will be a bit longer, so start checking around the 22-minute mark and go from there.
Why did my bars come out dry?
The most common reason is baking a little too long. Next time, pull them 2 minutes earlier and let them cool completely before slicing so they finish setting up on the pan.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Peanut Butter Sugar Cookie Bars
INGREDIENTS
Cookie Bars
- 1 cup unsalted butter softened
- 1 cup creamy peanut butter
- 1 cup granulated sugar
- 1 cup light brown sugar packed
- 2 large eggs
- 2 tsp vanilla extract
- 2 and 1 2 cups all purpose flour
- 1 tsp baking powder
- 1 2 tsp baking soda
- 1 2 tsp fine salt
- 2 tbsp granulated sugar for topping optional.
Peanut Butter Frosting Optional
- 1 2 cup unsalted butter softened
- 1 2 cup creamy peanut butter
- 2 cups powdered sugar
- 2 tbsp milk plus more as needed
- 1 tsp vanilla extract
- pinch of salt.
INSTRUCTIONS
Prep and Dough
- Heat oven to 350 F and grease a 9 by 13 inch baking pan or line with parchment
- whisk flour baking powder baking soda and salt in a bowl
- beat butter peanut butter granulated sugar and brown sugar until light and fluffy
- beat in eggs and vanilla until smooth
- mix in dry ingredients just until combined and do not overmix.
Bake and Finish
- Press dough evenly into prepared pan and smooth the top then sprinkle with topping sugar if using
- bake until edges are lightly golden and center is set 18 to 22 minutes and do not overbake for chewy bars
- cool completely in pan before slicing.
Frosting Optional
- Beat butter and peanut butter until creamy then mix in powdered sugar vanilla salt and milk until smooth and spreadable
- spread over cooled bars and chill briefly for cleaner cuts.
