Make the cake.  Preheat oven to 350 degrees F/ 325 degrees F convection.  Oil an 8 or 9 inch cake pan.

In a large bowl, beat the oil and sugar until lightened in texture and fully combined.  Beat in the vanilla, espresso, and the eggs, one at a time.  Stir in half the flour followed by the milk.  Stir in the remaining flour, baking powder, and chopped carob or chocolate.

Pour into the prepared pan and bake 25-30 minutes until golden brown and a toothpick inserted in the center comes out with a few crumbs.

Stir together the coffee, bourbon, and maple syrup and brush it over the hot cake.  Cool completely.

Make the frosting.  In a medium microwave safe bowl, place the butter, carob or cocoa powder, espresso, vanilla, syrup, and milk.  Microwave on high in 30 second increments, stirring in between, until fully melted.  Stir in the bourbon.  If the mixture is thick, but pourable, pour it over the cake.  If not, slowly stir in more milk until it is the proper consistency.

Finish the cake with finely grated carob or dark chocolate, slice and serve.  Cake may be stored at room temperature up to 4 days or frozen, wrapped in parchment and foil and placed in a zipper bag, for up to 3 months.  Thaw in the microwave about 1 minute.