Step 1Heat the oven to 350 degrees. Butter a 9x5-inch loaf pan, line the bottom and sides with parchment and grease the parchment. (Alternatively, butter and flour a 6-cup bundt pan.)
Step 2Combine the stout and molasses in a large saucepan over high heat and bring to a boil. Turn off the heat and add the baking soda. Allow to sit until the foam dissipates.
Step 3Meanwhile, whisk together the eggs and the granulated and brown sugars in a bowl. Whisk in the oil.
Step 4In a separate bowl, whisk together the flour, ground ginger, baking powder, cinnamon, cloves, nutmeg and cardamom.
Step 5Combine the stout mixture with the egg mixture, then whisk this liquid into the flour mixture, half at a time. Add the grated ginger and stir to combine.
Step 6Pour the batter into the loaf pan and bake until the top springs back when gently pressed, 1 hour. Do not open the oven until the gingerbread is almost done or the center may fall slightly. Transfer to a wire rack to cool.