1 cup regular rolled oats, plus additional
2 cups whole wheat flour
1/2 cup brown sugar
2 teaspoons baking soda
1 teaspoon baking powder
1/2 teaspoon salt
1/4 cup melted butter
2 teaspoons vanilla extract
1 cup buttermilk
1 (12 fluid ounce) can or bottle Guinness® beer
Preheat oven to 425 degrees F (220 degrees C). Grease an 8×8 inch baking pan.
Mix together the oats, flour, sugar, baking soda, baking powder, and salt in a bowl. In a separate large bowl, stir together the butter, vanilla, buttermilk, and Guinness® beer. Pour the flour mixture into the beer mixture, and gently stir until well blended. Pour batter into the prepared baking pan, and sprinkle with additional oats if desired.
Bake in preheated oven for 30 minutes, then turn the temperature down to 400 degrees F (200 degrees C), and bake for an additional 30 minutes. Turn the oven off, open the door, and allow to cool for 30 minutes in the oven before turning out onto a wire rack.