Peanut Butter Swirl Brownies

Name: Peanut Butter Swirl Brownies
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Cuisine: American
Ingredients: 4 oz dark chocolate, chopped ((112g - about 3/4 cup)); ½ cup unsalted butter ((113g)); ½ cup granulated sugar ((100g)); ½ cup brown sugar, packed ((100g)); 2 large eggs; 1 teaspoon pure vanilla extract ((4g)); ⅔ cup all-purpose flour ((80g)); ¼ cup cocoa powder ((21g)); 1 teaspoon salt ((3g)); ½ teaspoon espresso powder ((1g)); ¼ cup natural salted creamy peanut butter**, warmed until pourable ((67g))