In two large glass mugs divide brewed espresso. Add 1 tablespoon sugar to each and stir until dissolved, then mix into each 1 tablespoon rum and 1 tablespoon orange liqueur. Holding tablespoon facedown over side of mug, drizzle 1/2 cup cream over back of spoon so most of cream accumulates atop coffee. Repeat with second mug. Garnish with curled orange rinds, if desired.