Peanut Butter Chocolate Chip Oatmeal Cookie Bars

February 22, 2023

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by thenostalgiccrumb

Peanut Butter Chocolate Chip Oatmeal Cookie Bars

These peanut butter chocolate chip oatmeal cookie bars are chewy, soft, and packed full of all the good stuff! Baked in a 9×13” pan, these cookie bars are an easy crowd pleaser!

There are things that just naturally exist in the same space. Like cereal and milk, Mr. “KC” and the Sunshine Band, carbs and Netflix…you get the point. This same truth goes for these Peanut Butter Chocolate Chip Oatmeal Cookie Bars. Peanut butter, chocolate, and oatmeal are meant to exist together in cookie form. Take it one step further, and these bad boys are meant to be made into crowd-pleasing, big-batch, easy-peasy cookie bars. No scooping individual cookies here, folks. We’re going to make this as easy as possible by throwing a bunch of yummy peanut butter-oatmeal cookie dough studded with chocolate and peanut butter chips into a big ole’ 9×13″ pan. Bake, slice, serve, and everyone is happy.

What do I love most about these peanut butter chocolate chip oatmeal cookie bars? Aside from their chewy, gooey goodness and how easy they are to make, I LOVE the sweet-and-salty vibe they have going on. The base cookie dough is a peanut butter cookie dough, that, BONUS, has oatmeal that adds chewy texture and loads of chocolate and peanut butter chips that add decadence and gooey-ness. I like to top these with extra chips (because why not) and some flakey sea salt to really drive home that sweet-and-salty factor. These are thick, chewy, and meant for a crowd. And can you really go wrong with peanut butter and chocolate? I really don’t think you can.

Be sure to check out my notes for extra tips on how to bake these peanut butter chocolate chip oatmeal cookie bars up perfectly (hint: don’t over-bake them!). Happy baking, friends!

Peanut Butter Chocolate Chip Oatmeal Cookie Bars by The Nostalgic Crumb

What you’ll need to make these cookie bars:

Butter: Butter of course adds flavor and moisture to these cookie bars. Using melted butter instead of softened butter makes them a little more dense (in a good way!).

Creamy peanut butter: Using peanut butter in the cookie dough really drives home the peanut butter flavor! It also contributes to that sweet-and-salty vibe. Be sure to use regular, creamy peanut butter like JIF or Skippy, not the natural or organic kind which are too oily.

Brown sugar + granulated sugar: A large amount of brown sugar makes these cookie bars chewy and flavorful, while the granulated sugar adds sweetness, tenderness, and softness.

Eggs: For binding and structure.

Vanilla: For extra flavor.

Flour: All-purpose flour adds structure.

Old-fashioned rolled oats: Using oats in these cookie bars gives them a great chewy texture! Be sure to use old-fashioned rolled oats, not quick or steel-cut oats.

Baking soda + baking powder: For a little leavening power.

Kosher salt: For balance.

Cornstarch: A little bit of cornstarch makes these cookie bars extra soft.

Chocolate chips + Peanut butter chips: Chocolate chips and peanut butter chips throughout these cookie bars (plus some sprinkled on top) makes them gooey, flavorful, and extra decadent. I use semisweet chocolate chips, but feel free to substitute dark or milk chocolate. I use these peanut butter chips.

Flakey salt for topping (optional but highly recommended!).

Peanut Butter Chocolate Chip Oatmeal Cookie Bars by The Nostalgic Crumb

FAQs:

Why is this recipe primarily listed in grams? I develop my recipes in grams because weighing your ingredients is the best, most accurate way to bake. Baking is a science and precision is key to success! Measuring cups are not standardized, and what’s more, the way each baker uses them varies drastically, which ultimately gives you inconsistent (and sometimes negative) results. For instance, did you know that scooping flour out of a canister can give you 50% more flour than what’s called for in the recipe? By weighing your ingredients rather than using measuring cups, you can confidently know that you are using the correct amount of each ingredient, giving you greater success & delicious results. I highly recommend using a kitchen scale, like this one when you bake. Plus, it makes clean up a lot easier!

What kind of peanut butter should I use? Be sure to use regular, creamy peanut butter like JIF or Skippy. I personally always reach for JIF peanut butter. Don’t use natural or organic peanut butter as these are too oily and won’t work in this recipe.

Can I use quick oats? I don’t recommend using quick oats. Stick with the old-fashioned rolled oats!

What’s the best pan for these cookie bars? For best results, use a metal 9×13” baking pan. I use this pan from USA Bakeware.

Peanut Butter Chocolate Chip Oatmeal Cookie Bars by The Nostalgic Crumb

A few notes before you bake:

To ensure these cookie bars are soft, chewy, and gooey, be careful not to over-bake them. You’ll know it’s time to pull them out of the oven when they’re golden brown, the edges are set, and the center still has a little “wiggle” to it. The center will continue to set as they cool!

When it comes to cooling, I recommend letting the bars cool completely before cutting into squares. This allows the cookies to set, making them much easier to slice and serve!

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Peanut Butter Chocolate Chip Oatmeal Cookie Bars by The Nostalgic Crumb

Peanut Butter Chocolate Chip Oatmeal Cookie Bars

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  • Author: Molly
  • Prep Time: 15 minutes
  • Cook Time: 30 minutes
  • Total Time: 45 minutes
  • Yield: 24 cookie bars 1x
  • Category: Bars and One-Tin Bakes, Cookies
  • Method: Baking
  • Cuisine: Dessert, Snack

Description

These peanut butter chocolate chip oatmeal cookie bars are chewy, soft, and packed full of all the good stuff! Baked in a 9×13” pan, these cookie bars are an easy crowd pleaser!


Ingredients

Scale
  • 226 (1 cup) unsalted butter
  • 264 gm (1 cup) creamy peanut butter (not natural or organic)
  • 240 gm (1 cup, firmly packed) light brown sugar
  • 100 gm (1/2 cup) granulated sugar
  • 2 large eggs, at room temperature
  • 2 teaspoons vanilla extract
  • 219 gm (1 3/4 cups, spoon and leveled) all-purpose flour
  • 80 gm (1 cup, spoon and leveled) old-fashioned rolled oats
  • 1 teaspoon baking soda
  • 1/4 teaspoon baking powder
  • 1 teaspoon kosher salt
  • 1 teaspoon cornstarch
  • 220 gm (1 cup) semisweet chocolate chips, plus more for sprinkling
  • 165 gm (3/4 cup) peanut butter chips, plus more for sprinkling
  • Optional garnish: flakey salt

Instructions

  • Preheat the oven to 350°F. Lightly grease a 9×13″ baking pan with non-stick spray and line with parchment paper; set aside.
  • Melt the butter in a small saucepan set over medium heat, stirring occasionally. Add the warm melted butter and peanut butter to the bowl of a stand mixer fitted with the whisk attachment. Turn the mixer on low speed and whisk until the butter and peanut butter are fully combined.
  • Add the brown sugar and granulated sugar to the bowl and mix on medium speed until combined. Next, mix in the eggs and vanilla extract. Switch to the paddle attachment on your mixer.
  • In a separate bowl, add the flour, oats, baking soda, baking powder, kosher salt, and cornstarch, and whisk to combine. Add the dry ingredients to the peanut butter mixture and mix on low speed until just combined.
  • Add the chocolate chips and peanut butter chips to the bowl and mix on low speed for just a few seconds until the chips are evenly distributed throughout the dough.
  • Pour the dough into the prepared pan and smooth into an even layer. Sprinkle additional chocolate and peanut butter chips over the top, along with flakey salt, if using.
  • Bake until golden brown and the center is set but still has a little “wiggle” to it, about 30 to 34 minutes. I like to under-bake these just slightly as the will continue to bake and set as they cool in the pan. Don’t overbake these!
  • Allow to cool in the pan completely before cutting into squares.

Notes

Storage: Keep leftovers in an airtight container at room temperature for 3 to 5 days.