• Preheat oven to 350℉.

Brownie Batter

• Whisk together melted butter and both sugars in a bowl.
  6 tablespoons salted butter, melted, ¾ cup granulated sugar, ⅓ cup light brown sugar, packed
• Then, add the egg and vanilla, and whisk again until smooth.
  2 teaspoons vanilla extract, 1 large egg
• Stir together the flour, cocoa, and salt.
  ½ cup all purpose flour, ⅓ cup cocoa powder, ¼ teaspoon salt
• Add flour/cocoa/salt mixture to the wet ingredients and stir just until you don't see the flour anymore (don't overmix!).

Blondie Batter

• Using another bowl, whisk together melted butter and both sugars.
  2 tablespoons granulated sugar, ⅔ cup light brown sugar, packed, 6 tablespoons salted butter, melted
• Then, add the egg and vanilla, and whisk again until smooth.
  1 large egg, 2 teaspoons vanilla extract
• Stir together the flour and salt.
  1 cup all purpose flour, Pinch of salt
• Add the flour/salt mixture to the wet ingredients and stir just until you don't see the flour anymore (don't overmix!).

Assembling Batter In The Baking Pan

• Either grease your brownie pan or line it with parchment paper.
• Place about one-fourth of the brownie batter in one corner of the brownie pan and then another one-fourth in the opposite corner. Then, place half of the blondie batter in the other two corners (one-quarter of the batter in each corner). Spread each dollop of batter out to cover the bottom of the pan.
• For the second layer, place dollops of brownie batter over top of the blondie batter, and vice versa, and spread it out, so there are alternating layers of brownie batter and blondie batter.
• Completely optional - Using a butter knife, make swirls throughout the batter, to give it a pretty appearance when baked.

Baking

• Bake on the middle rack of the oven for 40 to 45 minutes, or until a toothpick inserted in the middle comes out mostly clean.
• Let cool completely in the pan before slicing.
• Enjoy!