Prepare the Crust: In a large bowl, mix 1½ cups graham cracker crumbs, 1/3 cup sugar, and 6 tbsp melted butter.Line an 8x8 pan with parchment or foil, leaving overhang for easy removal. Spray with non-stick spray. Press the crust firmly into the pan and refrigerate for 1 hour.
Make the Peanut Butter Layer: In a bowl, combine 2 cups peanut butter, ½ cup softened butter, a pinch of salt, 1 teaspoon vanilla extract, and 3 cups confectioner's sugar using clean hands or a spoon. Press evenly over the chilled crust.
Add Pretzels & Chocolate: Arrange a single layer of pretzels over the peanut butter. Crush the remaining pretzels and set aside. Melt milk chocolate chips with 2 tbsp shortening according to package directions. Pour over the bars and sprinkle with crushed pretzels.
Set & Serve: Refrigerate for 30 minutes, then cut into squares and enjoy!
