Preheat the oven to 325°F and position a rack in the center of the oven. , Lightly grease an 8" round pan or line with a reusable pan liner or parchment round. , To make the cake: In a large bowl, whisk together the flour, sugar, cocoa powder, gingerbread spice, salt, baking powder, and baking soda. , In a medium bowl, whisk together the water, oil, molasses, eggs, and vanilla. , Pour the wet ingredients into the dry ingredients and whisk until smooth. Add the chopped chocolate and use a flexible spatula to stir until evenly distributed. , Transfer the batter into the prepared pan. , Bake the chocolate gingerbread cake for 40 to 45 minutes, until the center feels firm and a toothpick or thin knife inserted into the center comes out clean. (If baking with Measure for Measure Flour, bake the cake for 45 to 50 minutes, as gluten-free baked goods often take a bit longer to bake through.) , Remove the chocolate gingerbread cake from the oven and allow it to cool in the pan while you prepare the glaze. , To make the glaze: In a small bowl, whisk together the confectioners’ sugar, gingerbread spice, and salt. Starting with the smaller amount of water, drizzle in 1 teaspoon at a time until the glaze reaches a thick, molasses-like consistency. If you’d like a thinner glaze, add more water. , Transfer the glaze to the center of the cake. If your glaze is thick, use a small offset spatula to spread it to the edges. If your glaze is thinner, it will spread evenly over the surface of the chocolate gingerbread cake on its own. Serve warm or at room temperature. , Storage information: Store leftover chocolate gingerbread cake, covered, at room temperature for several days; un-glazed cake can be frozen for longer storage.