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.
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.