Prepare the sourdough mixture: The night before, or at least 6-12 hours ahead, mix the active sourdough starter with the all-purpose and whole wheat flours and warm water in a large bowl. Stir until fully combined, cover, and let the mixture ferment at room temperature for 6-12 hours. This fermentation process gives the cake its signature sourdough tang and makes it easier to digest.

Preheat the oven to 350°F (175°C) and grease an 8x8-inch baking dish or loaf pan.

Mix the wet ingredients: In a medium bowl, whisk together the molasses, honey (or maple syrup), melted butter, egg, vanilla extract, and spices (ginger, cinnamon, cloves). Once combined, add the fermented sourdough mixture and stir well. The batter will be thick and rich.

Activate the baking soda: In a small bowl, dissolve the baking soda in 2 tablespoons of hot water. Quickly stir this into the batter. The baking soda will react with the sourdough starter and molasses, helping the cake rise and giving it a light, fluffy texture.

Bake: Pour the batter into the prepared pan and bake for 30-40 minutes, or until a toothpick inserted into the center comes out clean. The edges will be slightly crisp, and the top of the cake should be golden brown.

Cool and serve: Allow the gingerbread cake to cool in the pan for about 10 minutes before turning it out onto a wire rack to cool completely. Serve warm with a dollop of whipped cream or a drizzle of maple syrup, if desired.