These cookie bars will have you celebrating every time you make them! My simple to make Gooey Chocolate Peanut Butter Cookie Bars are great to take to parties, you’re in for a treat!!
If you love cookie bars like we do, try our Fruity Pebbles Cookie Bars too!

Cookie Bars
Oh how I love chocolate and peanut butter together. My cookie bars are perfect for taking to potlucks or any party! I’ve combined my peanut butter cookie dough from last week with a cake mix I turned into the chocolate cookie layer and topped it with marshmallows and chocolate chips. I’m in love with these bars!
Why You’ll Love This Recipe
- Only A Few Ingredients To Get. This simple cookie bar recipe just has a few ingredients which makes it a breeze to make!
- Chocolate Peanut Butter Combo. Not sure there is a better flavor combination than chocolate and peanut butter. These bars will quickly become your new favorite treat to make.
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What You’ll Need
Here are the ingredients you’ll need to make these chocolate peanut butter bar cookies at home. See the recipe card located at the bottom of the post for full details.
- Peanut Butter Cookie Dough– You can use a refrigerated cookie dough from the grocery store or make your own.
- Devil’s Food Cake Mix– Find cake mixes in the baking section of the grocery store.
- Butter– I use salted butter for my recipes. Unsalted is fine too.
- Egg– For consistency, I use large eggs in my cooking and baking.
- Mini Marshmallows– Find mini marshmallows in the baking section of the grocery store.
- Chocolate Chips– Milk chocolate or semi-sweet chocolate chips work great in the recipe.
How To Make Chocolate Peanut Butter Cookie Bars
Preheat Oven and Prepare Baking Dish. Preheat oven to 350 degrees F. and line 9 x 13 inch baking dish with parchment paper.
Peanut Butter Cookie Dough Layer. Press peanut butter cookie dough layer into baking dish. I used THIS recipe. Use whatever peanut butter cookie dough recipe you’d like.
Prepare Cake Mix Dough. Place cake mix, butter and egg into a large bowl. Mix until dough consistency forms. Press over peanut butter cookie layer.
Marshmallows. Top with marshmallows and chocolate chips.
Bake. Bake for 35-40 minutes until baked through. Let cool completely then cut into bars and serve room temperature.
Recipe Tips For Success
- Prepare Cookie Dough Ahead of Time. If you can make your peanut butter cookie dough ahead of time, you’ll find this will save lots of time the day you plan to bake the recipe.
- Use Store Bought Cookie Dough If Needed. If you don’t feel like making your own cookie dough, you can run up to the grocery store and get some store bought peanut butter cookie dough that will work just fine too.
- Use A Plastic Knife. You will find that by using a plastic knife to cut your bars into squares, it prevents sticking.

How To Serve
Serve these gorgeous bar cookies cut into squares served room temperature or slightly warmed for your next party or family dinner.
Leftovers
Store any leftover cookie bars in an airtight container for up to 3 days.
Try More Easy Cookie Bars Recipes
Gooey Chocolate Peanut Butter Cookie Bars
Equipment
- Oven
- 9 x 13 inch baking dish
- parchment paper
- mixing bowl
- mixing spoon
- measuring cups
- measuring spoons
- plastic knife
Ingredients
- 2 cups prepared peanut butter cookie dough
- 1 box Devil’s Food Cake Mix
- 1 stick salted butter softened
- 1 large egg
- 2 cups mini marshmallows
- 1 cup milk chocolate chips
Instructions
- Preheat oven to 350 degrees F. and line 9 x 13 inch baking dish with parchment paper.
- Press peanut butter cookie dough layer into baking dish. Use whatever peanut butter cookie dough recipe you’d like. Place cake mix, butter and egg into a large bowl. Mix until dough consistency forms. Press over peanut butter cookie layer. Top with marshmallows and chocolate chips.
- Bake for 35-40 minutes until baked through. Let cool completely then cut into bars and serve room temperature.
Notes
- Prepare Cookie Dough Ahead of Time. If you can make your peanut butter cookie dough ahead of time, you’ll find this will save lots of time the day you plan to bake the recipe.
- Use Store Bought Cookie Dough If Needed. If you don’t feel like making your own cookie dough, you can run up to the grocery store and get some store bought peanut butter cookie dough that will work just fine too.
- Use A Plastic Knife. You will find that by using a plastic knife to cut your bars into squares, it prevents sticking.
How gooey and delicious! Peanut butter and chocolate are the best!
Looks delicious! The combination of all those ingredients looks absolutely sinful (in the very best possible way)!
xx, Caitlin
http://www.wandererandwolf.com
I’m all for a loaded bar treat!! YUM!
I made this for dessert yesterday and it was very good. I did add some peanut butter and butter scotch chips just because I had them.
Oh man these look so good and so simple!
Im drooling over here!
Oh my goodness I am seriously going to have to make these today! Wow!
Rachel
Simply Rachel Nicole
Yummmy!!!!!
Love everything about these! I would love an entire pan 🙂
I would gladly take a few of these to get me through this Monday!
Oh these are my kind of treat!
THOSE LAYERS!! Gorgeous. I’ll take a dozen, please 🙂
Just saw these in my email. Oh my goodness Jenny. I could eat these for breakfast this morning!
LOVE love love this treat recipe!
It’s ridiculous how easy to awesomeness is!