How to Prepare:

• Step 1: Prepare the Brownie Batter - In a large mixing bowl, cream together 1 cup of softened butter, 1 cup of brown sugar, and 1 cup of granulated sugar until light and fluffy. Add in 2 large eggs and 1 tablespoon of vanilla extract, mixing well until combined.
• Step 2: Combine Dry Ingredients - In a separate bowl, whisk together 3 cups of all-purpose flour, 2 teaspoons of cornstarch, 3/4 teaspoon of kosher salt, and 1 teaspoon of baking soda. Gradually incorporate the dry ingredients into the wet mixture, stirring until just combined. Fold in 2 cups of chocolate chips.
• Step 3: Bake the Brownies - Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking pan and pour the brownie batter into the pan, spreading it evenly. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Allow the brownies to cool completely.
• Step 4: Prepare the Brownie Base - In a new bowl, melt 1 cup of butter. Add 1 cup of cocoa powder, 1/4 teaspoon of espresso powder, and 1/2 teaspoon of kosher salt. Mix until creamy, then stir in 1 cup of brown sugar and 1 cup of granulated sugar. Add 4 large eggs and 2 teaspoons of vanilla extract, mixing until smooth. Fold in 1 cup of all-purpose flour and 1 cup of chocolate chunks, and optional chopped pecans.
• Step 5: Bake the Brownie Base - Pour the brownie base batter over the cooled brownie layer in the pan. Bake again at 350°F (175°C) for 30-35 minutes. Let it cool before cutting into squares.
• Step 6: Assemble the Sundae - Place a generous piece of the brownie in a bowl. Top with a scoop of chocolate ice cream. In a small saucepan, melt 3 tablespoons of butter and whisk in 1/4 cup of sugar, 2 tablespoons of flour, and 1/3 cup of cocoa powder. Gradually add in 2 cups of whole milk, stirring until thickened. Pour this chocolate sauce over the brownie and ice cream.