In a smaller bowl, blend egg, milk, canola oil and whiskey. Add the wet mixture to the dry mixture and stir together until most of the dry spots and lumps are gone {but don't overmix}.
Divide the batter evenly among tins, filling a little over halfway full. Bake for about 18-20 minutes -- bake time will depend on the type of vessel you're using.
When they're done, a toothpick inserted in the center will come out mostly clean with some moist crumbs on it. Let the cakes cool for about 10 minutes before carefully removing from tins. Cool completely before topping with whipped cream.
Cut each cake in half. Scoop whipped cream into a piping bag. Pipe cream onto the bottom layer, then top with the other half of the cake. Pipe cream onto the top of each cake.
Garnish with a sprinkle of cocoa powder and a chocolate covered espresso bean if desired. It's best to assemble these just a few hours before serving. Keep whipped cream refrigerated until ready to use.