Preheat your oven to 175°C (350°F) and line a 9x9 inch baking pan with parchment paper, leaving some overhang for easy removal.
Melt the butter or coconut oil in a microwave-safe bowl until it’s just bubbling and fragrant.
Stir in the peanut butter until the mixture is smooth and creamy, with a slightly glossy appearance.
Add the brown sugar and vanilla, mixing well until everything is combined and the sugar starts to dissolve, filling your kitchen with a warm aroma.
In a separate bowl, whisk together the flour, baking soda, and a pinch of salt to ensure an even distribution.
Gradually fold the dry ingredients into the wet mixture using a spatula, stirring just until combined and a sticky dough forms.
Gently fold in the chocolate chips, distributing them evenly throughout the dough for pockets of melty chocolate.
Press the dough evenly into the prepared pan, smoothing the top with the spatula so it’s level and compacted.
Bake for 15 to 18 minutes, until the edges turn a golden brown and the center is just set but still slightly soft.
Remove from the oven and let the bars cool in the pan for about 10 minutes, allowing them to firm up and develop their chewy texture.
Transfer the bars to a wire rack using the parchment overhang, then let them cool completely before slicing into squares for serving.
Enjoy these chewy, chocolate-studded peanut butter bars as a nostalgic treat or quick snack—store leftovers in an airtight container at room temperature for up to 3 days.