Preheat oven to 350 degrees.

In a medium bowl, stir flour, baking soda, salt and spices for the cake together and set aside.

In a small bowl, whisk together molasses and water. Set aside.

In the bowl of a stand mixer, beat butter and sugar together until creamy.  Beat in eggs, one at a time, beating well after each. Gradually flour mixture, alternating with the molasses mixture, until the batter is blended.

Line the bottoms of four 9" round cake pans with wax paper and grease and flour the pans. Divide batter evenly between the pans.

Bake for 25 to 30 minutes, until toothpick comes out clean when inserted in the center. Cool in pans on cooling rack for 10 minutes. Turn cakes out onto the racks and cool completely, discarding the wax paper.

For the frosting, beat butter until very fluffy. Beat in sugar and milk in small batches, beating completely between each addition. The frosting should be very fluffy when you are done. Stir in vanilla, salt and melted chocolate. Frost the cake in between layers for a rustic look, or frost as you desire.