https://www.thekitchn.com/recipe-dark-molasses-gingerbread-cake-recipes-from-the-kitchn-155934

HALVED RECIPE:

84 g unsalted butter, cut into chunks
6 oz unsulphured dark or unsulphured blackstrap molasses
71 g brown sugar
33 g white sugar

211 g AP flour
1/4 tsp fine salt
1.25 tsp baking soda
1 tsp ground ginger
1/4 tsp cinnamon
1 tsp espresso powder (optional)

1 tsp vanilla
1 large eggs
177 ml / 0.75 cups whole milk

DIRECTIONS
1) Melt butter, molasses, and sugar until homogenous. Let cool.
2) Once cooled, whisk in vanilla, eggs, and milk.
3) Whisk dry ingredients together.  Pour wet ingredients into dry and mix to incorporate.
4) Bake at 350 F for 45-55 mins until skewer comes out clean. Let cool 20-30 mins before cutting.
5) Serve with cream cheese frosting (optional)

=====

RECIPE:

168 g / 12 tbsp unsalted butter, cut into chunks
12 oz / 1 1/2 cups unsulphured dark or unsulphured blackstrap molasses * (see Note below)
142.5 g / 3/4 cup brown sugar
66 g / 1/3 cup white sugar
422.5 g / 3 1/4 cups all-purpose flour
1/2 teaspoon fine salt
2 1/2 teaspoons baking soda
2 teaspoons ground ginger
1/2 teaspoon cinnamon
2 teaspoons espresso powder (optional)
1 teaspoon vanilla
2 large eggs, beaten
354 ml / 1 1/2 cups whole milk

Makes one 10" cake OR two 8.5 x 4.5 x 2.75" loaves.

Editor's Note on molasses: If you want the very dark, nearly black cake seen here, use unsulphured blackstrap molasses. Lighter molasses varieties will still work fine in this cake, but it won't be as dark or have any many bitter notes. If you want a lighter spice cake, then use regular molasses.