Preheat oven to 350°F. Line an 8x8 baking dish with parchment paper, set aside.
Mix butter and sugars until creamy, about 2-3 minutes. You may do this with an electric mixer or by hand.
1/2 cup butter, 1/3 cups brown sugar, 2 tbsp white sugar
Add in egg and vanilla and continue mixing. It will be smooth.
1 egg, 1 tbsp vanilla
Add in flour and baking soda. Don't overmix. The dough will be soft!
1 1/4 cups all-purpose flour, 1/2 tsp baking soda
Fold in chocolate chips.
1 cup semi-sweet chocolate chips
Spread half of the dough in the bottom of the prepared baking pan using your hands. Dollop the peanut butter onto the dough. Do not spread the peanut butter! This will leave you with thick peanut butter bites. You can use a tsp or tbsp.
1/2 cup creamy peanut butter
Top off with the remaining dough. It's okay if some peanut butter is showing, this will give you those nice swirls on top.
Bake in a preheated oven for 22-24 minutes. The bars will be a light brown on the edges. Remove from oven and cool completely in pan. If you cut open while they're warm, the bars will fall apart. Enjoy!