Preheat oven to 350°F (175°C). Grease a 13x9x2 inch baking pan and set aside.

In a large bowl, whisk together flour, sugar, baking soda, and salt.

Optional: Add 1 teaspoon of cinnamon to the flour mixture for added flavor.

In a saucepan, combine butter, cocoa powder, and 1 cup of water.

Heat the mixture over medium heat, stirring constantly, until it begins to move in the pan but not boil.

Remove the saucepan from the heat and pour the chocolate mixture into the dry ingredients.

Beat with an electric mixer until smooth.

Add eggs, buttermilk, and vanilla extract to the batter and mix thoroughly. The batter will be thin.

Pour the batter into the prepared baking pan.

Bake for 35-45 minutes, or until a toothpick inserted into the center comes out clean.

While the brownies are baking, prepare the frosting. (start around the 35-minute mark)

For the frosting, combine butter, cocoa powder, and buttermilk in a saucepan.

Bring the frosting mixture to a gentle boil over medium heat, stirring constantly.

Remove from heat and pour the frosting into a mixing bowl.

Add powdered sugar and vanilla extract to the frosting and mix until smooth.

Optional: Stir in chopped toasted pecans into the frosting.

Once the brownies are removed from the oven, place them on a wire rack.

Immediately pour the frosting over the warm brownies and spread evenly.

Let the brownies cool completely on the rack for at least an hour before cutting and serving.