1. Reserving 1 teaspoon ground espresso for garnish, brew 2 cups of espresso. Add sugar to the hot espresso, and stir to dissolve.

2. Prepare an ice bath. Place espresso mixture in a heat-proof glass bowl, and set in the ice bath, stirring until mixture becomes very cold.

3. Transfer espresso mixture to a 9-by-13-inch Pyrex baking dish, and place in freezer. Let stand until ice crystals start to form around the edges, about 45 minutes. Remove dish from freezer. Using the tines of a fork, stir the ice crystals into the center. Return dish to freezer. Stir the ice crystals every 30 minutes until all the liquid has frozen into soft, fine crystals, about 2 hours.

4. Place whipping cream in a chilled bowl, and whip until soft peaks form. Divide granita among four glasses or serving bowls. Top each with a dollop of whipped cream, and sprinkle remaining teaspoon ground espresso over tops. Serve immediately.