Delicious, sophisticated brownies that are great during the holidays as well as to finish a Mexican meal. While there are a lot of steps, it's actually a pretty easy dish to make and enjoy. Adapted from "Layers of Flavor" by Ray Overton.
Grease and flour a 13x9x2 baking dish and set aside (can use a mix of cocoa and flour to prevent white edges around finished brownies) In a big bowl (preferably by hand, NOT mixer), combine well the sugar, flour, cocoa, baking soda, salt and cinnamon.
Add melted butter, eggs, vanilla, and Kahlua, and stir just until blended (do not overmix).
Fold in chopped nuts, if you are using them.
Put batter in prepared baking dish, evening out the batter with a spatula.
Bake for 40- 45 minutes or until the edges of brownies begin to pull away from the sides of the dish.
Remove from the oven and put dish on wire rack to cool.
Immediately sprinkle dark chocolate chips over top of hot brownies.
Lighly place a sheet of aluminum foil over dish to hold in and reflect heat.
After about 5 minutes, when chips are melted, spread over the brownies with a spatula.
Immediately sprinkle white chocolate over the frosting, and lightly cover dish with the foil again.
After about 2 minutes, when chocolate is melted, gently swirl them into the dark chocolate to create a marbleized look.