Instructions

• Line an 8-inch or 9-inch square baking dish with parchment paper, leaving an overhang on two opposite sides for lifting the bars; (optional) use a 9x13-inch pan if you prefer thinner bars.
• In a large mixing bowl, combine 3 cups old-fashioned oats and 1 cup of the semisweet chocolate chips. Add 1 cup creamy peanut butter and 1 teaspoon vanilla extract and stir until the mixture is evenly combined; set aside.
• In a small saucepan, combine 2 cups granulated sugar, ½ cup milk, ½ cup unsalted butter, and ½ teaspoon salt. Heat over medium, stirring to dissolve the sugar.
• Bring the mixture to a full boil (bubbles covering the entire surface). Once it reaches a full boil, continue to boil for 2 minutes.
• Remove the saucepan from the heat. Immediately pour the hot sugar-butter mixture evenly over the oat–peanut butter mixture.
• Quickly stir the combined mixtures until all the oats are moistened and the mixture is uniform.
• Transfer the mixture into the prepared pan and use the back of a spoon (or a spatula) to press it evenly and firmly into the pan.
• Sprinkle the remaining 1 cup semisweet chocolate chips over the top and gently press them into the surface.
• Let the bars sit at room temperature until set, about 30 minutes. Use the parchment overhang to lift the set bars from the pan and cut into squares. Store in an airtight container at room temperature for up to 1 week.