Peanut Butter Oatmeal Bars

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Thick oatmeal bars with peanut butter streusel and a creamy, peanut butter frosting drizzle. These hearty peanut butter oatmeal bars will satisfy your hunger cravings and your sweet tooth.

Peanut Butter Streusel Oatmeal Bars - Tastes of Lizzy T

Do you guys know how Tastes of Lizzy T got started? It all began as a school project during Maddie’s 6th grade year. She was barely 12 at the time, but she loved baking and writing, so we thought it would be fun if she started a food blog. After all, lots of other people were food blogging and it didn’t look that hard.

She started by having a free little site on Blogger.  She made the recipes, she did the writing, and I took most of the pictures. We quickly realized a few things:

1. Food blogging was fun. To create a recipe, share it on social media (even if our Facebook following was only 10 at the time) and have people actually tell us that it looked delicious pretty much made our day!

2. Food blogging was a lot of work. For a newly 12-year old to keep up with the demands of blogging and learning everything that it takes to grow a blog, I knew I was going to have to make a commitment to help.Peanut Butter Streusel Oatmeal Bars - Tastes of Lizzy T

Fast forward two years later. Maddie is now a teenager who still loves to bake, write and is developing her photography skills.  But she’s also busy with school, sports, church and friends. Which leaves little ol’ me to be taking over much of the work that blogging requires. Busy-ness to a certain extent is good for me, though. When my mind is idle and bored, I tend to get myself in trouble. So having an on-the-side hobby that has quickly turned into a mostly-full-time job is necessary and good for me.

I try to still have Maddie write one post a week so she continues to develop her blog-writing skills. But what she is truly passionate about is baking. Most of the baked goods you see on our site have been baked by Maddie.

That includes these beautiful little Peanut Butter Oatmeal Bars.

Maddie comes up with her own ideas to try at times, but the majority of the time, I tell her what she needs to bake for the day. And when it includes peanut butter and oatmeal, two of her favorite things, she is more than happy to oblige. I love to see her face light up as I explain to her layer-by-layer the recipe that has developed in my mind.

Peanut Butter Streusel Oatmeal Bars - Tastes of Lizzy T

These baked peanut butter oatmeal bars have a thick, hearty oatmeal cookie texture. I had plans to call them “blondies”, but once I tasted them, I knew they were more of a hearty oatmeal bar instead of a soft, chewy blondie.

Peanut Butter Streusel Oatmeal Bars - Tastes of Lizzy T

Peanut butter streusel and a peanut butter glaze top these bars. Yes, you could serve just the bars, or just the bars with the streusel, but when you add all three layers, you get a deliciously sweet topping that pairs so nicely with the oatmeal cookie bars on the bottom.

I like to use my stand mixer because it takes virtually no arm-power, but as long as your butter is soft enough, you can make the batter with just a bowl and a spoon.

Peanut Butter Streusel Oatmeal Bars - Tastes of Lizzy T

If you love peanut butter, cookies and all things oatmeal-y, this recipe is for you!

Q: How old were you when you started baking?

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Need a dose of chocolate along with your peanut butter? Try these Buckeye Oatmeal Bars!


Peanut Butter Oatmeal Bars

4.84 from 12 votes
Thick oatmeal bars with peanut butter streusel and a creamy, peanut butter frosting drizzle.
Servings 12 servings
Prep Time 20 minutes
Cook Time 28 minutes
Total Time 48 minutes


  • 1/2 cup butter softened
  • 1/2 cup white sugar
  • 1/2 cup packed brown sugar
  • 1 large egg
  • 1/3 cup creamy peanut butter
  • 1/2 teaspoon baking soda
  • 1/4 teaspoon salt
  • 1/2 teaspoon vanilla
  • 1 cup all-purpose flour
  • 1 cup quick cook oats

Peanut Butter Streusel:

  • 1/2 cup plus 1 tablespoon all-purpose flour
  • 1/2 cup packed brown sugar
  • 1/4 cup butter softened
  • 3 tablespoons creamy peanut butter

Peanut Butter Drizzle:

  • 1/2 cup powdered sugar
  • 1/4 cup peanut butter
  • 2-4 teaspoons milk


  • Preheat the oven to 350 degrees.
  • In the bowl of a stand mixer, cream together the butter and sugars. Add the egg, peanut butter, baking soda, salt and vanilla. Mix well. Stir in the flour and oats. Mix just until combined. Spread in an 8x8 pan that has been sprayed with cooking spray.
  • In a small bowl, combine the ingredients for the streusel. Mix until the mixture is crumbly. Sprinkle over the top of the batter. Bake at 350 degrees for 25-28 minutes.
  • Once the bars have cooled to room temperature, mix the powdered sugar and peanut butter in a small bowl. Add the milk, a teaspoon at a time, until the mixture becomes a drizzling consistency.
  • Pour the peanut butter drizzle over the oatmeal bars. Allow the drizzle to set for 10 minutes, then serve.
  • Store any leftovers in an airtight container.


If you want the bars to come out cleanly for easy and neat cutting, line the baking pan with parchment paper before pressing the batter into the pan.


Serving: 77g | Calories: 361kcal | Carbohydrates: 41g | Protein: 6.5g | Fat: 20g
Author Lizzy T
Course Dessert
Cuisine American
Calories 361

Is peanut butter one of your favorite things? Try one of these favorites!

Find more peanut butter recipes here.

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Joanne Bruno
8 years ago

It’s definitely interesting to see how blogs evolve over time! Mine is nothing like what it was when I first started…and trust me, that’s a good thing! These bars sound FABULOUS. Anything peanut buttery sounds perfect to me!

Miranda @ Cookie Dough & Oven Mitt
8 years ago

These bars.. are gorgeous. My mouth is watering just looking at the photos! I was probably about Maddie’s age when I first started taking a huge interest in baking too. My Gram and I would bake together on the weekends. It’s awesome that you and her tag-team the food blog. I love it!

Kristen @ A Mind Full Mom
8 years ago

I am so in love with this recipe I may just get out the mixing bowl right now!

8 years ago

So much peanut butter….I love it!

1 year ago

4 stars
this recipe was great. however i modified it a bit at the end. i topped it with strawberries and used almond butter for the drizzle to keep it from tasting like just peanut butter and i’m glad i did. there’s quite a bit of peanut butter in this recipe

2 years ago

5 stars
This is the second time I’ve made these…..delicious! Thank you for sharing your recipe.

Susan Walters
2 years ago

5 stars
So i made 2 dozen oatmeal peanut butter cookies and they turned out so incredibly dry and crumbly..but the flavors were there..i didnt want to waste all of the ingredients..and my hard work..i started thinking what can i do with these? I came across lizzys recipe for oatmeal peanut butter bars and i thought hmmmm…i can work with this..i crumbled up all my cookies..added eggs and butter..made the streusel..and baked..omg..sooo good…i made the drizzle too…so lizzie turned my failed cookies into an amazing bar..thank you..huge success

Sara Gutierrez
3 years ago

Mine are still in the oven and I realized I somehow forgot the baking soda. 🤦 Please pray for my peanut butter bricks.

Isa B
3 years ago

5 stars
It turned out great i added chocolate chips to it too.

3 years ago

5 stars
WOW- the Peanut Butter Streusel Oatmeal Bars are incredibly delicious! Mine look just like the picture, & the hubby agrees that they are amazing. I was looking for a blondie-like recipe — something without chocolate— and this recipe was perfect. Will make these again & again for the peanut butter lovers in my life.

4 years ago

5 stars
Stumbled on this looking for oatmeal bars. Never had good luck combining oatmeal with peanut butter, somehow it comes off as this big glob of blandness for me usually, but this one really works! Totally addictive. Will note that the 8×8 pan was reeeeally more full than I expected it to be, to the point where I went and double checked to make sure I had the right pan listed. You could probably pull off putting it in a bigger pan, though I’d keep a sharp eye on it while baking so as not to overbake.

8 years ago

wondering how many calories would be per bar?

Medha @ Whisk & Shout
8 years ago

I love that blogging is something you do together! I started baking in 6th grade, too and I can’t believe it’s only really been just over five years since then, but my baking journey has evolved so much 🙂 These peanut butter oatmeal bars look decadent and delicious… pinning!

Hayley @ The Domestic Rebel
8 years ago

5 stars
Holy deliciousness! These oatmeal squares look divine, you guys. I’m so glad you and Maddie started blogging because your blog is one of my faves! You’re both so sweet and talented and have such a plethora of incredible recipes, including this one!

8 years ago

These look AWESOME. I’m on a major peanut butter kick right now and these are exactly what I need…