Sourdough Peanut Butter Oatmeal Chocolate Chip Cookie Bars

These sourdough peanut butter oatmeal chocolate chip cookie bars are a mouthful in more ways than one! All of the best elements of your favorite 3 classic cookies rolled into big, fat, chunky cookie bar squares.

Peanut butter, chewy oats, and melty chocolate chips are loaded in a 9×13 pan. If you love a fat, chewy cookie, these cookie bars are for you!

It’s an easy one-bowl sourdough discard recipe that doesn’t require scooping batches of cookies or rotating pans in and out of oven. Just mix, pour, bake, and ta-da! An easy sourdough dessert for any occasion that feeds a crowd.

There’s also no long fermentation time so these sourdough cookie bars can be made in under an hour!

If you love sourdough cookies, you’ll love my sourdough cowboy cookie bars and classic sourdough oatmeal chocolate chip cookie bars. If you’re an intense chocolate lover, my sourdough double chocolate chip cookies and sourdough discard brownies are for you!

Scroll down for the recipe card, followed by detailed step-by-step instructions (with photos). And a sample baking schedule.

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Sourdough Peanut Butter Oatmeal Chocolate Chip Cookie Bars Recipe

Sourdough Peanut Butter Oatmeal Chocolate Chip Cookie Bars

Annabelle

These sourdough peanut butter oatmeal chocolate chip cookie bars are all your favorite cookies rolled into big, fat, chunky cookie bar squares! Peanut butter, chewy oats, and melty chocolate chips are loaded in a 9×13 pan. If you love a fat, chewy cookie, these cookie bars are for you.

5 from 1 vote

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Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Course Dessert, Snack

Cuisine American

Servings 24 cookie bars

Calories 300 kcal

Ingredients

  

• 1 cup salted butter melted
• 1½ cup brown sugar
• 2 eggs
• ⅔ cup sourdough discard
• 3 teaspoons vanilla extract
• 1 cup creamy peanut butter
• 1 teaspoon salt
• 1 teaspoon baking soda
• 2 cups all-purpose flour
• 2 ½ cups quick oats
• 1 cup semi-sweet chocolate chips

Instructions

 

• Preheat oven to 350℉ (180℃). Line a 9×13 glass baking dish with parchment paper and set aside.
• Add melted butter and brown sugar to a mixing bowl and combine. Add eggs, sourdough discard, and vanilla extract. Mix to combine.
• Add peanut butter, salt, and baking soda. Mix well and scrape down sides of bowl with a spatula as needed.
• Add flour and oats and mix well. Fold in chocolate chips. The batter will be very thick so mix well and make sure you incorporate all the dough from the bottom of the bowl using a spatula.
• Scoop batter into parchment lined baked pan and spread evenly with a spatula. It will be thick so take your time, making sure to press it to the edges and corners. Sprinkle the top with a few additional chocolate chips and gently press them into the batter.
• Bake at 350℉ (180℃) for 28-32 minutes until golden brown all over, the edges are starting to crisp, and the middle is mostly set. Do not over-bake; the cookie bars will continue to set as they cool.
• Once cooled, slice, serve, and enjoy!

Notes

Batter – The batter for these sourdough cookie bars will be very thick so mix it well and scrape down the sides of the bowl. Make sure you spread the batter evenly in the baking pan.

Peanut butter – I recommend using creamy peanut butter for this recipe. You can use crunchy if you wish but the cookie bars may be more dry.

Oats – You can use either quick oats or old-fashioned oats for this recipe. Either one will work, but quick oats will give you a soft, fluffier cookie bar while old-fashioned oats will yield a chewier, denser cookie bar.

Chocolate chips – I use regular semi-sweet chocolate chips for this recipe but you can use mini semi-sweet or dark chocolate chips as well.

Baking – Just like when perfecting a chewy cookie, the key is to slightly underbake these cookie bars. It should be golden brown all over and the edges set with middle slightly underdone. It will continue to set as it cools so watch carefully that you don’t over-bake. Add just a couple minutes at a time of extra baking when nearing the perfect golden brown.

These sourdough cookie bars combine 3 classic cookie favorites–peanut butter, oatmeal, and chocolate chip–into one chunky cookie bar. They are thick while still being chewy and oh-so-soft.

I love making a big batch of cookie bars like this. They are the perfect dessert for a crowd! It makes a large 9×13 pan and there’s no scooping individual cookies. They’re quick to mix and bake to slice up into generous portions that leave everyone satisfied.

Why you’ll love this recipe

• It’s a combo of all your favorite cookies. Soft peanut butter, chewy oatmeal, and buttery chocolate chip rolled into one hefty dessert. The MVPs of the cookie world come together!
• They’re easy and quick! There’s no fermentation time with this sourdough discard recipe, no scooping individual cookies, and only one bake time. No waiting for batches to come out of the oven. You can make these sourdough discard cookie bars in under an hour.
• It feeds a crowd. This recipe makes 24 thick, chewy cookie bar squares. The portions are generous and it makes enough to feed a crowd in no time. 
• It’s a one-bowl recipe you can customize. Simply mix the ingredients together, pour in a pan, and bake. Could not be easier for busy bakers! You can add your own mix-ins like dried coconut or nuts to change it up.

Important Ingredients

Sourdough peanut butter oatmeal chocolate chip cookie bars use basic pantry staples. Take note for:

• Peanut butter – I recommend using creamy peanut butter for this recipe. You can use crunchy if you wish but the cookie bars may be more dry.
• Sourdough discard or active sourdough starter – Yes, you can use either one! Since you’re using sourdough discard or starter to enhance the flavor, you can use either one you have on hand.
• Oats – You can use quick oats or old-fashioned oats for this recipe. The texture will change somewhat based on what oats you use. For fluffier, softer bars, use quick oats. For more dense, chewier bars, use old-fashioned oats.  
• Chocolate chips – I use regular semi-sweet chocolate chips for this recipe, but you can mix it up. Mini semi-sweet chocolate chips, dark, or milk chocolate would also be good.
• Vanilla extract – Maybe I’m biased, but there is nothing like the flavor of homemade vanilla extract. I think it levels up any sweet treat recipe. Any kind of vanilla extract will do, but if you want to kick it up a notch, use homemade. I like this recipe from Natasha’s Kitchen.

A full ingredient list with exact amounts can be found in the recipe card above.

How to Make Sourdough Peanut Butter Oatmeal Chocolate Chip Cookie Bars (Step by Step)

Step 1: Preheat oven to 350℉ (180℃). Line a 9×13 glass baking dish with parchment paper and set aside.

Step 2: Add melted butter and brown sugar to a mixing bowl and combine. Add eggs, sourdough discard, and vanilla extract. Mix to combine.

Step 3: Add peanut butter, salt, and baking soda. Mix well and scrape down sides of bowl with a spatula as needed.

Step 4: Add flour and oats and mix well. Fold in chocolate chips. The batter will be very thick so mix well and make sure you incorporate all the dough from the bottom of the bowl using a spatula.

Step 5: Scoop batter into parchment lined baked pan and spread evenly with a spatula. It will be thick so take your time, making sure to press it to the edges and corners. Sprinkle the top with a few additional chocolate chips and gently press them into the batter.

Step 6: Bake at 350℉ (180℃) for 28-32 minutes until golden brown all over and the middle is mostly set. Just like when perfecting a chewy cookie, the key is to slightly underbake these cookie bars. They should be golden brown all over and the edges set with middle slightly underdone. It will continue to set as it cools so watch carefully that you don’t over-bake. Add just a couple minutes at a time of extra baking when nearing the perfect golden brown.

Don’t cut these cookie bars too soon! Give them time to cool and fully set in the middle or the center might be too gooey. Remember, the cool down process is an important step in creating that perfect, melt-in-your-mouth, chewy cookie bar.

Once cooled, slice, serve, and enjoy!

How to Serve

These sourdough peanut butter oatmeal chocolate chip cookie bars are best served to a crowd! This recipe makes a large 9×13 pan so think cookouts, family dinners, camping trips, or picnics. Anywhere you need to have a dessert ready for a dozen or more people, this is a great go-to.

They’re perfect for pretty much any occasion, but they’re particularly good for when you have to make a dessert ahead of time and transport it. They cookie bars are sturdy and can be served right out of the baking pan or stacked in an airtight container.

How to Store

These sourdough cookie bars can be stored in an airtight container for up to 5 days. Or cover the baking pan tightly with plastic wrap. I like how these bars don’t dry out and just get softer the next day!

You can also wrap them individually in plastic wrap after they are completely cool. Don’t try to do it before they’re cool or you’ll have a melty, gooey mess on your hands! But once they’re cool, wrap them individually in plastic wrap to add to lunches, a picnic basket, or cooler for camping or kayaking.

How to Freeze

To freeze these sourdough cookie bars, wrap completely cooled, individual cookie bar squares in plastic wrap. Then place them in a freezer bag and press gently to get rid of the air.

Freeze for up to 1 month for maximum freshness. To thaw, place on the counter overnight and reheat before enjoying.

Frequently Asked Questions

These sourdough peanut butter oatmeal chocolate chip cookie bars are all the best elements of 3 of the most classic cookies. They’re big and chewy while being flavorful and wholesome.

I hope you try these for your next party or adventure and spread the love! We love them and I hope you will too.

Remember to leave a rating and comment sharing how you enjoyed this recipe!