In a saucepan over med – low heat, bring sugar, butter, and Guinness to a boil. In a glass bowl combine the remaining dry ingredients. Use a whisk to quickly beat eggs into hot liquid. Mix liquid into dry ingredients. After ingredients are completely mixed place in loaf pan and bake for 40 minutes. Insert toothpick in middle to check for doneness. Toothpick should be almost clean, If dough sticks to toothpick, bake for an additional 5 – 10 minutes. Cool on a cooling rack. Bun can be stored in a cool dry place for up to 3 days or refrigerated for up to 7 days.