1-Getting peanut butter brownies just right starts with preheating your oven to 350°F (175°C) and preparing an 8×8-inch baking pan by spraying it with baking spray and lining it with parchment paper for easy removal. Melt the unsalted butter over medium heat, then take it off the heat and whisk in half of the semisweet chocolate chips until smooth and glossy. Let this mixture cool slightly before transferring it to a large bowl for the next steps.

2-In another bowl, sift together the all-purpose flour, unsweetened cocoa powder, and salt to ensure there are no lumps. Now, add the granulated sugar, light brown sugar, eggs, and vanilla extract to the chocolate mixture, whisking until everything blends into a smooth batter. Gently fold in the dry ingredients just until combined, then mix in the remaining chocolate chips for extra bursts of chocolate.

3-Pour the batter into your prepared pan and spread it evenly. Drop teaspoonfuls of creamy peanut butter over the top and use a knife or skewer to swirl it lightly, creating that beautiful marbled effect. Bake for 40 to 45 minutes, or just 35 minutes if you prefer a gooey center; if the peanut butter starts to brown too much, cover the pan with foil after 25 minutes. Let the brownies cool completely before slicing to keep them from falling apart, with total preparation time around 50 minutes including 10 minutes of prep and 35-40 minutes of baking.