Preheat oven to 350 degrees.
Prepare an 8-inch round or square cake pan with cooking spray.
In large bowl, beat the butter and sugar with electric mixer until fluffy. Beat in eggs. Add vanilla into butter mixture.
In a separate bowl, combine the flour, ground espresso, baking powder and salt. Mix well. Add dry ingredients to butter mixture, pour batter into greased cake pan. Bake for 30 minutes or until toothpick inserted into center comes clean. Allow cake to cool completely. Remove cake from pan and poke holes all over the top of the cake with a handle of a wooden spoon. Return the cake to the cake pan.
In a small saucepan, bring espresso to a boil and stir in the sugar until it dissolves. Remove from heat and stir in whiskey. Pour syrup over the cake. Place cake in refrigerator for one hour. Beat whipping cream until fluffy, add whiskey, brewed and cooled espresso/coffee and powdered sugar.
Place cake on serving platter. Cut cake in half horizontally and spoon 1/2 of topping cream mixture on bottom layer. Replace top layer and top each piece with a dollop of remaining cream mixture.
Serve with Door County Coffee Highlander Grogg, Irish Crème or Dublins Delight.