A baking tray of chocolate-frosted peanut butter bars cut into squares, with chopped peanuts on top. Text reads: “Lunch Lady Peanut Butter Bars. Did your school serve these?”.

Would you like to save this?

We'll email this post to you, so you can come back to it later!

A hand lifts a square oat bar topped with chocolate and chopped peanuts from a stack on a tray, with more bars and ingredients visible in the background.

Lunch Lady Peanut Butter Bars

Thick, soft peanut butter bars topped with rich chocolate frosting. Just like the classic school cafeteria favorite, but even better at home.

No ratings yet

Print Pin Rate

Course: Dessert

Cuisine: American

Prep Time: 15

Cook Time: 25

Total Time: 40

Servings: Bars

Calories: 508kcal

Author: Wendy

Equipment

9×13 baking dish
mixing bowls
hand mixer or stand mixer
spatula

Ingredients

For the Peanut Butter Bars:

1 cup unsalted butter softened
1 cup creamy peanut butter
1 cup granulated sugar
1 cup brown sugar
2 large eggs
1 teaspoon vanilla extract
2 cups all-purpose flour
1 teaspoon baking soda
½ teaspoon salt

For the Chocolate Frosting:

½ cup unsalted butter softened
¼ cup unsweetened cocoa powder
3 cups powdered sugar
¼ cup milk
1 teaspoon vanilla extract

Instructions

1️⃣ Prep

Preheat oven to 350°F.
Grease a 9×13 baking dish or line with parchment.

2️⃣ Make the Peanut Butter Base

In a large bowl, cream butter, peanut butter, granulated sugar, and brown sugar until light and fluffy.
Add eggs and vanilla. Mix well.
In a separate bowl, whisk flour, baking soda, and salt.
Gradually add dry ingredients to wet ingredients. Mix until just combined.
Spread evenly into prepared pan.

3️⃣ Bake

Bake 20 to 25 minutes until edges are lightly golden and center is set.
Do not overbake. These should stay soft.
Let cool completely before frosting.

4️⃣ Make the Frosting

Beat butter and cocoa powder until smooth.
Add powdered sugar, milk, and vanilla.
Beat until creamy and spreadable.
Spread evenly over cooled bars.

5️⃣ Slice & Serve

Cut into squares and try not to eat three in a row. I’m not judging if you do.

Notes

✨ Optional Twists

Sprinkle flaky sea salt on top
Add mini chocolate chips to the batter
Swap half the frosting for peanut butter frosting
Top with chopped peanuts

💡 Make-Ahead Tip

These keep beautifully covered at room temp for 3 to 4 days. They also freeze well.

🔎 Notes

Do not overbake. The bars should remain soft.
Sprinkle flaky sea salt on top for a sweet-salty twist.
Bars can be stored covered at room temperature for 3–4 days.

Disclaimer:

Any nutritional data I provide is an approximation and actual dietary information can vary based on ingredients and proportion sizes.

Nutrition