Peanut Butter Lunch Lady Bars

These Peanut Butter Lunch Lady Bars are the ultimate nostalgic treat, famously served in school cafeterias across the country. What makes them so special is the “hot batter” method—boiling the butter and peanut butter before mixing—which creates a unique, dense, yet melt-in-your-mouth texture similar to a peanut butter brownie. Finished with a fudgy, cooked frosting, these are a peanut butter lover’s dream.

Peanut Butter Lunch Lady Bars

Ingredients:

How To Make Peanut Butter Lunch Lady Bars:

Step 1: Prep and Preheat: Preheat your oven to 400°F. Grease a large 13×18-inch rimmed sheet pan (jelly roll pan). This recipe makes a large batch, perfect for a crowd or bake sale.

Step 2: Mix the Dry and Wet: In a large bowl, whisk together the flour, sugar, baking soda, and salt. In a separate small bowl, whisk the 1/2 cup milk, vanilla, and the 2 beaten eggs together.

Step 3: The Hot Base: In a medium saucepan, melt the 1 cup of butter and 1 cup of peanut butter over medium heat.

Tip: Let the mixture reach a gentle boil before removing it from the heat. This high temperature helps dissolve the sugar in the next step, leading to that signature “lunch lady” texture.

Step 4: Combine the Batter: Slowly stir your dry ingredients into the hot peanut butter mixture. Once combined, stir in the milk and egg mixture until the batter is smooth.

Step 5: Bake: Spread the batter into your prepared sheet pan. Bake for 20 minutes until a toothpick comes out clean. Let the bars cool completely before frosting; if the bars are hot, the frosting will soak in rather than sitting on top.

Step 6: Cook the Frosting: In a small saucepan, melt the remaining 1/2 cup butter and 1/2 cup peanut butter. Bring to a boil, remove from heat, and stir in the 2 tablespoons of milk and the powdered sugar until smooth and glossy.

Step 7: Frost and Set: Pour the warm frosting over the cooled bars and spread quickly with an offset spatula. Let them sit at room temperature until the frosting is firm to the touch.