Brownies:

Preheat oven to 350 degrees.

Heat the butter, water and cocoa until the butter is melted and the ingredients are very hot.  The mixture doesn’t need to come to a boil.  This can be done in a saucepan on the stovetop or in the microwave.

Combine the flour, sugar, baking soda and salt; add to cocoa mixture. Stir in the buttermilk, vanilla and beaten eggs.

Mix by hand or at low speed with a hand mixer until smooth (do not overmix).

Pour into greased 10″ x 15″ cookie sheet and bake for 20-25  minutes, until a toothpick inserted in the center comes out clean.

While the cake is baking, prepare the frosting.

Frosting:

Combine the first three ingredients in a saucepan and cook over low heat until the butter is melted and the ingredients are very hot, but not boiling.  You can also do this in the microwave, stopping and stirring a few times in between.

Sift the icing sugar to remove lumps, and add to butter/coca/buttermilk mixture along with vanilla.  Beat with mixer until smooth.

Allow cake to cool for 5-10 minutes and pour icing over warm cake.  Spread evenly with an off-set spatula or knife.  The heat of the cake will melt the icing to form a thick, glossy glaze.

NOTE: No buttermilk? Make one cup of buttermilk by using 1 tablespoon white vinegar plus enough milk to make 1 cup.