Make the cake
Preheat oven to 350 degrees and line an 8-inch round cake pan with parchment paper.
Whisk eggs, water, oil, molasses, and vanilla in a large bowl. Add in baking mix and spices; whisk until well blended. Pour batter into prepared pan and bake for 30 to 35 minutes, or until cooked through. Allow cake to cool completely.
Make the icing
Whisk all ingredients together until smooth. The icing should be thick so it just runs down the sides of the cake. If the icing is too thin, add more powdered sugar. If it is too thick, add a teaspoon or two of water. Cover the top of the cake with icing.