• Preheat oven to 350°F (180°C) and prepare an 8x8 metal baking pan with parchment paper. Allow some paper to hang over the sides to make it easier to remove from the pan later.

For the brownies:

• Start by adding the aquafaba to a large mixing bowl. Using an electric hand mixer, whisk it for a couple minutes to whip air into it and bubbles form. Add in the sugar and continue whisking for another minute until a thin paste forms. You can also use a whisk by hand but it will take more time.
  1/3 cup aquafaba, 1 cup sugar
• Melt the chocolate in a microwave-safe dish in 30-second intervals stirring in between until melted (can also use a double boiler but that takes more time). Add the peanut butter, melted chocolate, milk, and vanilla extract and stir, using a silicone spatula or spoon until combined.
  3 tbsp all-natural peanut butter, 3 tbsp unsweetened non-dairy milk, 1 tsp pure vanilla extract, 3.5 oz dark chocolate bar
• Add the cocoa powder and flour. I chose to sift it in to avoid and lumps but you can skip that if you don't have the time. Then add the salt and stir to combine just until no more dry flour is visible.
  1/3 cup dutch process cocoa powder, 3/4 cup white whole wheat flour, 1/2 tsp salt
• Transfer the brownie batter to the prepared baking pan and smooth out to create an even layer. Set aside.

For the blondies:

• Add the aquafaba, sugar, peanut butter, and vanilla extra to a second large mixing bowl. Stir well to combine (no whisking needed for this batter).
  1/4 cup aquafaba, 3/4 cup sugar, 1/4 cup all-natural peanut butter, 1 tsp pure vanilla extract
• Add the flour, baking powder and salt and stir until just combined. Then fold in the chocolate chunks/chips. The batter will be thicker than the brownie batter, more like cookie dough consistency.
  3/4 cup white whole wheat flour, 1/2 tsp baking powder, 1/4 tsp salt, 1/3 cup dark chocolate bar
• Add the blondie batter to the pan on top of the brownie batter and spread out into an even layer. Swirl the two together if desired using a spatula or butter knife ,weaving back and forth through both batters to combine; careful not to mix too much.

Bake:

• Bake on the center rack for 40-45 minutes until the center of the brownie blondies no longer jiggles and a toothpick inserted into the center comes out with no wet batter (some melted chocolate from the chocolate chunks is ok).
• You can tell that your brownie blondies are done baking when they have a nice crackled top and they don't wobble in the center.
• Allow to cool in the pan for 10-15 minutes before slicing. For gooey-er brownies you can slice in the pan after 10-15 minutes of cooling, or for more denser, cookie bar texture, remove from pan and allow to cool on a wire rack completely before slicing.