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Loaded Oatmeal Blondies marry cookie bars and oatmeal cookies – clean out your pantry and fill these bars with your favorite things!

stacked oatmeal bars with m&ms baked in


The best part about this oatmeal bar recipe are the mix-ins. You can add whatever you want! It’s an easy way to clean out your pantry, just throw in 2 cups total of any add-ins. 

Bar cookies are just so much easier to make – just press them in the pan and bake. No need to chill dough, no need to worry about if they’ll spread too much. And if you’re like me and line the pan with foil, there is almost no clean up! #barcookiesforthewin

stacked oatmeal bars with m&ms baked in
ingredients in blondies

Ingredients in Oatmeal Bar Cookies

  • Unsalted butter: softened
  • Brown sugar: packed brown sugar – I prefer brown to white sugar
  • Egg: I use large eggs 
  • Vanilla extract: to bring out the flavor 
  • Salt: just a pinch to enhance flavor
  • Baking soda: for leavening (not baking powder)
  • Ground Cinnamon: a must when using oats in your recipe
  • All-purpose flour: be sure to use the right amount
  • Quick Cooking Oats: you can also use old-fashioned oats 
  • Mix-ins: 2 cups of any add-ins you want! I love using chocolate chips, M&Ms, almonds, walnuts, pecans – any kind of nuts or candy!
cookie dough in bowl.
cookie dough with M&Ms in bowl.
blondies in pan

How to make Oatmeal Cookie Bars

  1. Prepare- preheat the oven to 350°F. Line the pan with foil and spray with cooking spray.
  2. Mix- cream the brown sugar and butter in the bowl. Beat the eggs and vanilla until combined. Mix the salt, baking soda, cinnamon, flour and mix batter until combined. Stir in oats and your mix-ins.
  3. Transfer the cookie dough into the prepared baking dish 
  4. Bake for about 25 minutes. Then, let it cool completely before slicing into squares 
  5. Store in an airtight container for up to 4 days or freeze for up to 2 months!
stacked oatmeal bars with m&ms baked in

Variations

Luckily for you, this one cookie bar recipe has endless variations. Since you can add any mix-ins you want, you can save this recipe as your go-to treat and play around with different variations for each occasion or mood. 

Here are a few of my favorite ways to compliment an occasion with this one oatmeal cookie bar recipe: 

  • Add your favorite chocolate pieces. White, dark, milk or semi sweet chocolate 
  • You can’t ever go wrong with cinnamon raisin! 
  • Add colorful fun with m&ms!
  • Get the best of all worlds with a trail mix of pretzels, chocolate chips, granola, dried fruit and more! 
  • Add some chocolate covered espresso beans to the mix for a crunchy kick of caffeine! 

Get creative and add in whatever your heart desires at the moment. I love how this recipe is so easy to tailor to your mood. 

FAQs

How long do you bake oatmeal cookie bars?

Bake for about 25 minutes. The center should be jiggly when they come out. It will finish baking as it cools. 

Can you freeze oatmeal cookie bars?

Yes, you can! Freeze for up to 2 months and your oatmeal cookie bar will still be just as chewy good!

How do you know when oatmeal cookies are done?

Getting close to the 25 minute mark, you should see the edge brown and rise to a crisp. The center should still be soft and jiggly. Remove to finish baking while it cools. 

stacked oatmeal bars with m&ms baked in

Loaded Oatmeal Blondies

5 from 8 votes
Oatmeal Cookie Bars filled with anything you like – this is the perfect recipe to clean out your baking cabinet!
Prep Time 15 minutes
Cook Time 25 minutes
Total Time 40 minutes
Yield 24 bars
Serving Size 1 bar
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Ingredients
 

  • ½ cup (113g) unsalted butter , softened
  • 1 ¼ cups (250g) packed brown sugar
  • 1 large egg
  • 1 teaspoon vanilla extract
  • ½ teaspoon salt
  • ½ teaspoon baking soda
  • 1 teaspoon cinnamon
  • 1 cup (124g) all-purpose flour
  • 1 ½ cups Quick Cooking Oats
  • 2 cups of mix-ins (see note)
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Instructions

  • Preheat oven to 350°F. Line a 9×13” pan with foil and spray with cooking spray. (Foil is optional; I like using it for easy removal.)
  • Cream brown sugar and butter in the bowl of an electric mixer fitted with a paddle attachment. Add eggs and vanilla and beat until combined. Mix in salt, baking soda, and cinnamon. Add flour and mix until combined. Stir in oats. Stir in your mix-ins.
  • Press into prepared pan (dough is sticky, spray your hands with cooking spray to avoid it sticking to your hands). If you want, you can sprinkle a few more of your mix-ins on the top to make them look prettier (as I did with the mini M&Ms in the pictures).
  • Bake for about 25 minutes. (Be careful not to overcook – the center will still be jiggly when you take these out of the oven and they will finish cooking and firming up as they cool.) Cool completely before slicing into squares.
  • Store in an airtight container for up to 4 days or freeze for up to 2 months.

Recipe Video

Recipe Notes

Mix-Ins: Use anything you want! Just make sure to use 2 cups total of whatever you choose. Here are some ideas:
  • Chocolate Chips (White, milk, semi-sweet)
  • Butterscotch or peanut butter chips
  • M&Ms or Reese’s Pieces
  • Toffee Bits
  • Butterfinger Bits
  • Chopped Nuts
  • Chopped peanut butter cups
  • Shredded Sweetened Coconut

Recipe Nutrition

Serving: 1bar | Calories: 194kcal | Carbohydrates: 28g | Protein: 2g | Fat: 9g | Saturated Fat: 5g | Polyunsaturated Fat: 0.3g | Monounsaturated Fat: 1g | Trans Fat: 0.2g | Cholesterol: 18mg | Sodium: 78mg | Potassium: 86mg | Fiber: 1g | Sugar: 20g | Vitamin A: 130IU | Vitamin C: 0.003mg | Calcium: 27mg | Iron: 1mg
Nutritional information not guaranteed to be accurate
Course Dessert
Cuisine American
Author Dorothy Kern

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Other Favorite Oatmeal Cookies:

Easy Oatmeal Cookie Bars – these are loaded oatmeal blondies – add anything you like – we call these kitchen sink cookies!



Dorothy Kern

Welcome to Crazy for Crust, where I share recipes that are sometimes crazy, often with a crust, and always served with a slice of life.

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5 from 8 votes (5 ratings without comment)

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47 Comments

  2. Wait, you’ve only been in your house for 2 years? How did I not know this?? And send me any cleaning-out-the-house and packing-up-everything tips you have… I’m SO not looking forward to doing that this summer. And being out of commission for a few weeks. That is the one bad thing about food blogging… But these bars? YUM! I need to try the oatmeal blondie combo sometime soon!

    Reply

    1. It’s been 2 weeks since I baked anything and I’m getting shaky from the withdrawals…

      Reply

      1. Want to come over tomorrow and use my kitchen? Or even tonight, if you want! I’m doing minimal baking, so it’s all yours! 😉 I hadn’t photographed anything for over a week until I shot yesterday’s frappuccino… It felt so weird at first, but thankfully it was more like remembering how to ride a bike than I thought!

  3. You are definitely a genius, Dorothy! 😉 I love everything about these oatmeal blondies. I’m craving them now!!

    Reply

  4. I’ve been known to often claim that oatmeal is my enemy, because it’s healthy and I want my desert to be made entirely of chocolate. But then I usually go and bake something with oatmeal like 2 days later (my latest recipe involves oatmeal, too). What can I say, I change my mind a lot. Anyway, this recipe combines both, and I love it! I’m a huge fan of blondies, although I usually add peanut butter to mine. Call it an addiction 😉

    Reply

  5. As soon as I saw this recipe in my email feed, I knew I had to make it. For my mix-ins, I used some plumped raisins and apricots, and five different types of chips. The result: Fabulous! Thanks so much for the recipe. The next time I make it (and there WILL be a next time), I think I’m going to try to figure out how to incorporate some Biscoff spread.

    Reply

    1. That would be awesome! I haven’t done it, but you could probably reduce the butter just a bit, and add the same amount of biscoff as butter. You may just need a little more flour to compensate, but it’s a bar cookie, so if it’s gooey it doesn’t matter so much!

      Reply

      1. Thanks for the advice regarding the Biscoff. I was thinking about the butter-Biscoff exchange, but the addition of extra flour hadn’t occurred to me.

        After I posted my comment, I remembered that I also added a few sweetened chopped dates as part of my mix-ins. I keep them on hand for use in banana bread, and they’re pretty good in these blondies, too. Thanks again!!