These peanut butter Lunch Lady cookie bars are my nostalgic, soft, chewy dream dessert. Inspired by those classic cafeteria-style treats, they’re rich with peanut butter flavor, topped with a creamy, fudgy peanut butter frosting, and baked into easy-to-slice bars that are perfect for sharing—or keeping all to myself.
Why You’ll Love This Recipe
I love this recipe because it’s ridiculously simple to make, yet delivers all the cozy, school-lunchroom vibes I didn’t know I missed. The bars are soft and chewy with just the right amount of sweetness, and the frosting? It’s a smooth, peanut butter cloud that melts right into the warm bars. Whether I’m baking for a potluck, holiday tray, or just because, these are always a hit.
ingredients
(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)
For the bars:
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Unsalted butter
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Creamy peanut butter
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Granulated sugar
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Brown sugar
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Eggs
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Vanilla extract
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All-purpose flour
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Baking powder
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Salt
For the frosting:
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Creamy peanut butter
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Unsalted butter
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Milk
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Powdered sugar
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Vanilla extract
directions
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I preheat the oven to 350°F and grease a 9×13-inch baking pan.
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In a large bowl, I cream together the butter, peanut butter, granulated sugar, and brown sugar until smooth.
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I beat in the eggs and vanilla until fully combined.
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In a separate bowl, I whisk together the flour, baking powder, and salt. Then I slowly add it to the wet ingredients, mixing just until combined.
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I spread the thick batter evenly into the prepared pan and bake for 20–25 minutes, until the edges are lightly golden and the center is set.
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While the bars are still warm, I prepare the frosting by melting butter and peanut butter together in a saucepan or microwave, then whisking in the milk, powdered sugar, and vanilla until smooth.
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I immediately spread the frosting over the warm bars so it melts slightly into the top, creating that classic, soft-frosted finish.
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I let the bars cool before slicing into squares.
Servings and timing
This recipe makes about 24 bars.
Prep time: 15 minutes
Bake time: 25 minutes
Total time: 40 minutes
Variations
Sometimes I stir in mini chocolate chips or chopped peanuts for texture. I’ve also used crunchy peanut butter instead of creamy when I want more bite. If I’m feeling extra indulgent, I drizzle melted chocolate over the frosted bars or sprinkle with sea salt flakes for a sweet-salty kick. For a gluten-free version, I use a 1:1 gluten-free baking flour substitute.
storage/reheating
I store these bars in an airtight container at room temperature for up to 4 days. For longer storage, I keep them in the fridge, where they’ll last about a week. They also freeze beautifully—just wrap them tightly and freeze for up to 2 months. I let them thaw at room temp or microwave individual bars for 10–15 seconds to soften.
FAQs
Can I use natural peanut butter?
I prefer using regular creamy peanut butter like Jif or Skippy because it gives the bars the best texture. Natural peanut butter can make them oily or dry, depending on the brand.
Do the bars need to be frosted while warm?
Yes, I spread the frosting while the bars are still warm so it melts just a bit into the surface and creates that classic soft glaze.
Can I double this recipe?
Definitely. I double it for parties and bake it in two 9×13 pans or a larger sheet pan. Just keep an eye on the bake time—it may need a few extra minutes.
How do I know when the bars are done baking?
I check that the edges are lightly golden and the center is set. A toothpick inserted should come out with a few moist crumbs, not wet batter.
What’s the best way to cut clean slices?
I let the bars cool completely before slicing, and I use a sharp knife cleaned between cuts. For super neat edges, I chill the bars first.
Conclusion
These peanut butter Lunch Lady cookie bars are a nostalgic treat that delivers every time. They’re easy to make, rich in flavor, and perfect for any occasion. I love having a go-to recipe that brings back memories and satisfies every sweet tooth in the house. Once I make a batch, they disappear fast.
Print
Peanut Butter Lunch Lady Cookie Bars
- Prep Time: 15 minutes
- Cook Time: 25 minutes
- Total Time: 40 minutes
- Yield: 24 bars
- Category: Dessert, Bars
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Description
These peanut butter Lunch Lady cookie bars are soft, chewy, and topped with a fudgy peanut butter frosting—just like the nostalgic cafeteria-style dessert you remember. Perfectly sweet, rich in peanut butter flavor, and easy to slice into shareable squares, they’re a crowd-pleasing treat for any occasion.
Ingredients
For the bars:
- 1/2 cup unsalted butter, softened
- 1/2 cup creamy peanut butter
- 1/2 cup granulated sugar
- 1/2 cup brown sugar, packed
- 2 large eggs
- 1 tsp vanilla extract
- 1 1/4 cups all-purpose flour
- 1 tsp baking powder
- 1/2 tsp salt
For the frosting:
- 1/2 cup creamy peanut butter
- 1/4 cup unsalted butter
- 1/4 cup milk
- 2 cups powdered sugar
- 1 tsp vanilla extract
Instructions
- Preheat oven to 350°F. Grease a 9×13-inch baking pan.
- In a large bowl, cream together butter, peanut butter, granulated sugar, and brown sugar until smooth.
- Beat in the eggs and vanilla until fully combined.
- In a separate bowl, whisk together flour, baking powder, and salt. Gradually mix into the wet ingredients just until combined.
- Spread batter evenly into prepared pan. Bake for 20–25 minutes, or until edges are golden and center is set.
- While bars bake, prepare frosting: Melt peanut butter and butter together in a saucepan or microwave. Stir in milk, powdered sugar, and vanilla until smooth.
- While bars are still warm, spread frosting evenly over top. Let cool completely before slicing into bars.
Notes
- Use crunchy peanut butter for added texture.
- Add mini chocolate chips or chopped peanuts for mix-ins.
- Drizzle melted chocolate or sprinkle with sea salt flakes for an extra treat.
- For gluten-free, substitute a 1:1 gluten-free baking flour.
- Frosting spreads best over warm bars for that classic soft-glazed finish.
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