Preheat the oven to 350℉ and flour and butter a 13X18 baking sheet. Set aside.
Melt the butter, dark and semi-sweet chocolate separately. Set them aside to cool down slightly.
2 cups Butter, 2 cups Semi-sweet Chocolate, 6 ounce Dark chocolate
Use a whisk or a hand mixer to beat the eggs, vanilla, and sugar until well mixed.
2¼ cups Granulated sugar, 2 tablespoon Vanilla extract, 6 Eggs
Sift flour, cornstarch, espresso powder, baking powder, and salt. Use a rubber spatula to fold the dry ingredients into the wet ingredients. Do not overmix.
2 tablespoon Cornstarch, 2 tablespoon Espresso powder, ¾ cup All-purpose flour, 1 tablespoon Baking powder, ½ teaspoon Salt
In a separate bowl, mix the chopped nuts and chocolate chips. Toss the extra flour on them to coat them all. Add them to the batter and gently fold.
12 ounce Semi-sweet chocolate chips, 1½ cups Walnut, 1½ cups Pecan, 1 tablespoon Flour
Spread the batter on the prepared pan and drizzle the top with caramel sauce. This step is optional. Bake for 30-35 minutes. The top will form a shiny crust.
Let the brownie batch cool down before cutting. You can drizzle the top with melted chocolate and caramel sauce for extra flavour.