01 -
Set oven to 350°F. Grease and line a 9x13-inch baking pan with parchment paper.
02 -
In a large bowl, whisk melted butter and sugar until glossy. Add eggs one at a time, mixing thoroughly after each. Stir in vanilla extract.
03 -
Whisk flour, cocoa powder, salt, and baking powder in a separate bowl. Gently fold dry ingredients into wet mixture until just combined to maintain fudgy texture.
04 -
Spread half the batter into the pan. Drizzle half the caramel sauce. Add remaining batter and smooth top. Swirl remaining caramel over surface with a knife.
05 -
Bake in the center rack for 28 to 32 minutes or until a toothpick reveals moist crumbs. Cool completely on a wire rack.
06 -
Cut brownies into 16 squares. Place a large marshmallow on each square, securing with caramel if needed. Toast marshmallows with a kitchen torch or under broiler until puffed and lightly golden (optional).
07 -
Press two mini chocolate chips into each marshmallow to form eyes. Dust lightly with powdered sugar and drizzle additional caramel for a spooky finish.