Peanut Butter Lover’s Cookie Bars

January 7, 2020

It may be a bit of an American stereotype, but I really just love peanut butter. There’s something special about the combination of roasty, salty, and sweet that just gets me every time. If you’re like me, always buying the biggest jar of the tasty sandwich spread, you will definitely enjoy these gooey treats. With quadruple pb-power, peanut butter cookie bars are for the real lovers of the stuff!

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Although there’s a little bit of chocolate, I really wanted the focus of this recipe to be on the peanut butter itself. It’s an homage to a true classic ingredient I have often fallen back on as I started eating less meat throughout my life. It has its place in savory dishes, but here it’s oh so sweet.

Between the peanut butter cookie base, the mini cups throughout, the crushed cups on top, and finally a gooey drizzle – that’s a lot of peanut butter. But these aren’t overwhelming. The other ingredients really help to balance out that nutty flavor, making for a true dessert treat.

What You Need to Get Started

You can easily find all of the ingredients for these peanut butter cookie bars at your grocery store. You can also order online using Amazon Pantry, or try Amazon Fresh for grocery delivery.

Let’s Make Peanut Butter Cookie Bars

There’s nothing super complicated about these cookie bars. In fact, bars tend to be less work than cookies, because you bake it all at once for longer instead of doing batches. Plus, the outside ends up a bit more done than the middle, which means you can please chewy and crispy cookie lovers with one dish.

Before starting on the dough, preheat your oven and line a pan with parchment paper hanging over the edges, so the bars will be easy to remove and cut later. I used a glass pan, which tends to heat the edges more than the middle, for a dramatic difference. You can use a metal pan for less of a crust on these.

Begin the dough by creaming together butter and sugar in your stand mixer until it’s fluffy. Then you’ll mix in other liquid ingredients: peanut butter, vanilla, and eggs. I suggest using creamy peanut butter in this recipe, which will make for a nice, smooth dough.

Like most cookie recipes, use a separate bowl to whisk together all the remaining dry ingredients: flour, cornstarch, and baking soda. You might notice there’s no added salt here, which is because most peanut butters already contain plenty on their own. Mix it all together so there’s no baking soda pockets in your dough.

Add the dry ingredients to the mixer plus a little bit of milk, which will help the dough form together. You may need more milk depending on how your dough looks, so keep an eye on it while mixing. If it’s crumbly, add another splash. If it looks soft and doughy, you’re good.

Only mix the dough until it’s just combined, and there are no large lumps of flour. It’s always a good idea not to overmix cookie dough, which can make the cookie bars tough instead of gooey and chewy.

Once the dough is ready, add in the mini peanut butter cups to the bowl. And you can fill that measuring cup all the way, maybe a little bit heaping. Eat a couple too, I won’t tell anyone. Use a silicone spatula to fold the chips into the dough.

When you have a good distribution of peanut butter cups, it’s time to transfer the dough to your prepared pan. Use your silicone spatula again to scrape the bowl and get all that delicious, tasty dough into the pan.

Then gently press the dough, using your hands or the bottom of a measuring cup to push the dough into the shape of the pan. Be sure to get into all the corners, and be careful of any folds in the parchment.

Are you ready for peanut butter part three? It’s time to crush some Reese’s! I always keep a few of these in my freezer, but if you don’t, you may want to throw a couple in there a few hours before making these bars. They are easier to crush when slightly chilled.

I used a plastic bag and a wooden mallet to crush mine, but you can also break them apart with your hands, or use a rolling pin, the back of a heavy spoon, or even a knife to chop them.

Sprinkle the crushed cups evenly over the top of the dough, and give them a small press into the cookies, so they settle in nicely. Then you can place the entire pan in the freezer, covered loosely with some plastic wrap or foil and wait until it’s just a bit chilled.

Bake straight from the freezer if you’ve only left the pan in for ten minutes. If you want to prepare these ahead, you can freeze for longer. However, I suggest thawing the dough in the fridge overnight if you want to do that.

The cookie bars will be done after about 25-30 minutes. The best way to tell is to look for the dry edges, which will start to get a bit golden brown. Also, you can stick a toothpick right into the center.

It will look like the dough is still raw, but if the toothpick comes out clean, these are good to go. They’ll firm up a bit while they cool. In fact, you’ll want to let them set for about an hour before adding the drizzle on top.

To make the drizzle, use a small microwave-safe bowl to melt the butter along with some milk. Microwave in 15 second increments until the butter is melted. If it looks close, you can give the bowl a swirl, which will help it melt a bit faster.

Stir in the peanut butter until it’s nice and uniform. Then add the confectioner’s sugar in a little bit at a time, stirring until it’s smooth. The consistency should be fairly liquidy, but if needed, you can add a bit more warm milk.

Use the parchment paper to lift the cookie bars out of the pan and onto a cutting board. Then use a spoon to drizzle the topping over the bars. If you want more control over the look, feel free to use a pastry bag instead. Let it set for 5-10 minutes, then cut it into bars and serve.

Hey peanut butter lovers, these cookie bars are for you! With quadruple peanut butter goodness, you will love this sweet and gooey dessert.

How to Serve Cookie Bars

These cookie bars are best for dessert. Serve them with a glass of milk, or for something a bit warmer, try a chai white hot chocolate. If you’re looking for more of a kick, and want more peanut butter flavor, make some peanut butter cup boozy hot cocoa. Or for a little bit of contrast, try an amaretto old fashioned.

You can also add these to your next cookie tray. Include a few other options like cherry chocolate chip cookies, apple cider caramel stuffed snickerdoodles, plum jam newton-style cookie bars, and blueberry cheesecake cookies.

Use Up Leftover Ingredients

Print Recipe
5 from 1 vote

Peanut Butter Lover's Cookie Bars

Quadruple the peanut butter, for real fans! These cookie bars feature a pb dough, mini cups, crushed cups, and a drizzle on top - all peanut butter of course.
Prep Time10 minutes
Cook Time30 minutes
Total Time40 minutes
Course: Dessert
Cuisine: American
Servings: 16 bars
Calories: 263kcal


Peanut Butter Cookie Bars

  • ½ Cup Unsalted butter room temperature
  • ¾ Cup Brown sugar
  • ¼ Cup Granulated sugar
  • 1 Egg
  • 1 tsp Vanilla extract
  • ½ Cup Creamy Peanut Butter
  • 1 ⅓ Cups All-purpose flour
  • 1 Tbsp Cornstarch
  • 1 tsp Baking soda
  • ½-1 Tbsp Milk
  • ½ Cup Mini Peanut Butter Cups
  • 3 Reese's Peanut Butter Cups crushed

Peanut Butter Drizzle

  • 1 Tbsp Creamy Peanut Butter
  • 1 Tbsp Milk
  • 1 Tbsp Butter
  • 2 Tbsp Confectioner's Sugar


  • Preheat the oven to 350°F, with a rack in the center. Line an 8x8 baking pan with parchment paper, overhanging the edge on two sides.
  • In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and both sugars on medium-low until fluffy, about 1-2 minutes. Add in the egg, vanilla extract, and peanut butter, and continue mixing until thoroughly combined.
  • Meanwhile, in a small bowl, whisk together the flour, cornstarch, and baking soda until combined. Add the dry ingredients into the mixer bowl with ½ Tbsp of the milk, and mix on low until just combined. If the dough seems dry or crumbly, add the rest of the milk while mixing.
  • Use a silicone spatula to fold in the mini peanut butter cups until distributed. Then transfer the dough to the prepared pan. Use the bottom of a measuring cup or your hands to press the dough into the pan.
  • Sprinkle the crushed peanut butter cups and top evenly, and then place the entire pan in the freezer for 10 minutes.
  • Remove from the freezer and bake for 25-30 minutes, until the edges are starting to look dry, and a toothpick inserted into the center comes out clean. Let the cookie bars cool for at least an hour.
  • While the bars are cooling, prepare the drizzle. In a small microwave-safe bowl, combine the milk and butter. Microwave in 15 second increments until the butter is melted. Stir in the peanut butter until uniform. Then stir in the confectioner's sugar 1 Tbsp at a time until smooth.
  • Once cool, use the parchment paper to carefully lift the cookie bars out of the pan. Use a spoon to top the bars with the peanut butter drizzle, and then cut into 16 squares. Serve immediately, or store in the fridge for 3-4 days.


  • I recommend using creamy peanut butter, not crunchy in this recipe. I have not tried making these with other nut butters, but if you try it out let me know how it goes!
  • Make ahead tip: You can bake, cool, and cut the bars a few days in advance. I suggest adding the drizzle shortly before serving. It will taste fine to store these in the fridge after drizzling, but you may lose some of the appearance. 

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4 thoughts on “Peanut Butter Lover’s Cookie Bars

  1. Yum! These look so delicious and moist! I love how you share the whole process with photos, too. It always makes me more excited to give them a try when I see how tasty they are! 🙂

  2. These look absolutely delicious!! I’m really into making bars at the moment and I was literally just thinking about adding PB so I will deffo do this at some point. Thank you for sharing 🙂 x

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