The first thing I do is brew my coffee so it has time to cool before I need it. It's important to cool the coffee so it doesn't cook the eggs when we combine the two.
Preheat oven to 350F degrees. Spray a 9 x 13 baking dish with nonstick cooking spray.
In a large bowl, combine all the dry ingredients (flour, sugar, cocoa, baking soda, baking powder and salt.) Gently whisk to combine.
In a separate bowl combine all the wet ingredients (eggs, oil, milk, cooled coffee & vanilla extract.)
Then slowly add in dry ingredients to wet ingredients. Add a little at a time, mix, then add a little more until it is all incorporated.
Once combined, pour cake batter into prepared baking dish.
Bake for about 30-40 minutes until a toothpick comes out clean from the center. The cake should also spring back to the touch and not jiggle in the center.
Allow cake to cool completely, then start on frosting.
In a medium bowl, using an electric mixer or your stand mixer, mix butter until smooth.
Then mix in marshmallow fluff.
Next, stir in molasses.
Finally, mix in powdered sugar and spices.
Mix until smooth and creamy.
Spread onto cooled cake. Slice and serve. Keep cake refrigerated!
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Notes
If you aren't in the mood to make a cake from scratch, you can just use a dark chocolate boxed cake mix and instead of the water it calls for, just substitute it with brewed coffee.
Don't want a gingerbread frosting? Just leave out the molasses and spices and add about a teaspoon of vanilla extract for a lovely, soft marshmallow frosting.