1. Preheat & Prepare: Preheat your oven to 400°F (200°C). Grease a large cookie sheet or line it with parchment paper for easy removal.
2. Mix Dry Ingredients: In a bowl, whisk together the flour, sugar, baking soda, and salt. Set aside.
3. Combine Wet Ingredients: In a separate bowl, whisk together ½ cup milk, vanilla extract, and beaten eggs. Set aside.
4. Cook Peanut Butter Mixture: In a medium saucepan, melt 1 cup (2 sticks) of unsalted butter with 1 cup of peanut butter. Bring to a gentle boil, then remove from heat.
5. Prepare the Batter: Gradually add the flour mixture to the melted peanut butter mixture, followed by the milk and egg mixture. Mix until smooth and well combined.
6. Bake: Spread the batter evenly onto the prepared cookie sheet. Bake for 20 minutes or until a toothpick inserted into the center comes out clean. Let the bars cool completely before frosting.

Making the Frosting 🍪

1. Heat Butter & Peanut Butter: In a saucepan, melt 1 stick of butter with ½ cup of peanut butter. Bring to a gentle boil.
2. Add Milk & Sugar: Remove from heat and add 2 tablespoons of milk. Gradually whisk in the powdered sugar until smooth and creamy.
3. Frost the Bars: Pour the frosting over the cooled cookie bars, spreading evenly to the edges. Allow the frosting to cool and set before cutting into squares.