Modified from Cooking Light
1 3/4 cups flour
1 tsp baking soda
1/2 tsp baking powder
1/2 tsp salt
6 tbsp. butter, softened
3/4 cup dark brown sugar
2 large eggs
1/2 tsp vanilla
1/2 cup stout beer (so like Guinness)
1/2 cup sour cream (fat free)
1/4 cup maple syrup
baking spray
Preheat oven to 350. Combine flour, baking soda, baking powder and salt. Place butter and brown sugar in large mixing bowl and beat until well blended. Add eggs, 1 at a time, beating after each addition. Beat in vanilla. Combine beer, sour cream and syrup, stirring well with a whisk. Beating on low speed, add flour mixture and beer mixture alternatively to butter mixture until just combined.
Put into a loaf pan (9 by 5) coated with baking spray. Bake at 350 for 40-45 minutes or until it passes the toothpick test. Cool for 10 minutes in pan on a wire rack. Remove from pan, cool completely on wire rack.
They had instructions for a glaze which I completely ignored.