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–+ servings
cutting board with a row and partial row of cut lunch lady peanut butter bars.
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5 from 2 votes

Lunch Lady Peanut Butter Bars

Lunch Lady Peanut Butter Bars from The Food Charlatan. They are insanely good, and come in clutch with the pb/chocolate. We start with a thick chewy peanut butter oatmeal cookie base, but then we go and top it with a layer of straight up peanut butter, PLUS a rich chocolate frosting that is like the crackly frosting top on a Texas Sheet Cake. Y'AAALLLLLL it's so good. This dessert feeds a crowd and is perfect for potlucks, reunions, summer BBQs, Father's Day, or literally any day after school!
Prep Time30 minutes
Cook Time15 minutes
Total Time45 minutes
Course: Dessert
Cuisine: American
Servings: 30
Calories: 392kcal
Author: The Food Charlatan

Ingredients

For the bars

  • 1 cup butter softened
  • 1 and 1/2 cups brown sugar packed
  • 1/2 cup granulated sugar
  • 1 cup peanut butter
  • 2 large eggs
  • 2 teaspoons vanilla
  • 2 cups all purpose flour spooned and leveled
  • 1 teaspoon baking soda
  • 1 teaspoon kosher salt or sea salt
  • 1 cup quick oats
  • 1 cup old fashioned oats

For the peanut butter frosting

  • 1 and 1/2 cups creamy peanut butter

For the chocolate frosting

  • 3/4 cup butter
  • 3/4 cup cocoa
  • 1 cup powdered sugar
  • 1/2 cup sour cream
  • 2 teaspoons vanilla
  • 1/4 teaspoon kosher salt
  • 2 cups powdered sugar plus an extra 1/2 cup, if you want thick frosting

Instructions

  • Preheat the oven to 350 degrees F. Line a 11x17 inch (half baking sheet) pan with parchment paper, or spray with nonstick spray.
  • Make the bars: In a large bowl or stand mixer, add 1 cup softened butter. Beat until soft and creamy. Add and 1 and 1/2 cups packed brown sugar. Add 1/2 cup granulated sugar. Beat well for a full minute, scraping down the sides and bottom at least once. The mixture should be light and fluffy.
  • Add 1 cup peanut butter (I'm a Jif girl). I love to use my adjustable measuring cup for this! Beat in the peanut butter until the mixture is smooth.
  • Add 2 eggs and 2 teaspoons vanilla extract and beat well, scraping the sides and bottom.
  • Add 2 cups all purpose flour, using a spoon to add flour to the cup, then leveling it off. (You don't want it packed in). Don't stir yet. Add 1 teaspoon baking soda and 1 teaspoon kosher salt (or sea salt.) Use your teaspoon to mix the soda and salt into the flour a bit.
  • Add 1 cup quick oats and 1 cup old fashioned oats.* Use the beaters to mix the dry ingredients into the butter mixture, but don't over do it. Scrape the sides of the bowl and mix one more time, then stop right away. You don't want to over mix this, or the cookie layer will turn out tough.
  • Scrape the dough into the prepared half baking sheet pan. The dough is quite sticky. If it's annoying to do this with your spatula, get your hands a little damp, and press the dough in with you fingers.
  • Bake the cookie layer at 350 for 14-17 minutes. The edges should be golden, and it should have a light golden hue all across the top. It might have puffed up and even cracked in the middle; that's fine, it will go down, plus we're frosting it anyway. Set aside to cool at least 10 minutes.
  • Add the peanut butter layer. Meanwhile, add 1 and 1/2 cups peanut butter to a bowl. Microwave for about 30 seconds, until it's easier to pour. Spread the peanut butter all across the center of the bars, not covering the edges, which will be lifted up a bit higher than the center.
  • Set aside to cool. I like to stick mine in the fridge or freezer to speed this up. You need the peanut butter to be at least room temperature (if not cold) so that when you add the frosting, it doesn't mix together. We want clean layers. Maybe.
  • Make the frosting. Add 3/4 cup butter and 3/4 cup cocoa to a medium saucepan. Stir together over medium heat until it comes to a boil, then remove from the heat.
  • Add 1 cup powdered sugar and whisk well. (This helps cool down the mixture.) Add 1/2 cup mounded sour cream, 2 teaspoons vanilla extract, and 1/4 teaspoon kosher salt. Stir well.
  • Use a hand mixer to beat in the remaining 2 cups powdered sugar, getting all the lumps out. (You can also use a whisk and some elbow grease). If you like a thicker frosting, add another 1/4 or 1/2 cup powdered sugar.
  • Add the frosting. Once the peanut butter layer is totally room temperature or chilled, add the chocolate frosting on top. Use an offset spatula to spread it not quite to the edges of the peanut butter. It looks pretty to be able to see the peanut butter and chocolate layers. That said, this does leave the edge-eaters rather frosting-less, so spread all the way to the edge if you are feeling compassionate toward them.
  • Storage: Keep covered on the counter! They also taste phenomenal when chilled. Just keep the air out!

Notes

*You can use all old fashioned oats, or all quick oats. In my opinion, old fashioned makes it a little too chewy, and quick oats doesn't give it enough, so I like to mix. But either way will work!

Nutrition

Calories: 392kcal | Carbohydrates: 42g | Protein: 7g | Fat: 23g | Saturated Fat: 10g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 9g | Trans Fat: 0.4g | Cholesterol: 43mg | Potassium: 200mg | Fiber: 2g | Sugar: 28g | Vitamin A: 373IU | Vitamin C: 0.03mg | Calcium: 35mg | Iron: 1mg