Preheat the oven to 350ºF (180ºC). Spray a 9 x 5-inch (23 x 13cm) loaf pan with nonstick spray, or butter, then line the bottom with a rectangle of parchment paper. Spray or butter the parchment paper. (You can also bake it in a bundt pan. See headnote.)
Heat the molasses and stout in a medium-to-large saucepan until it comes to a boil. Turn off the heat and stir in the baking soda. Set aside to let the foam subside and allow the mixture to cool
In a small bowl, whisk together the flour, ground ginger, baking powder, cinnamon, cloves, nutmeg, and cardamom.
In a large bowl, whisk the eggs with the granulated and brown sugar until there are no lumps, then whisk in the oil.
Whisk in the cooled molasses mixture into the eggs, then gradually whisk in the dry ingredients, stirring only in one direction. (To prevent lumps.) Stir in the fresh ginger.
Scrape the batter in the prepared pan, filling it three-quarter's full. (See headnote.) Bake until a toothpick inserted in the center comes out relatively clean, 50 minutes to 1 hour.