In a heavy large saucepan, stir together the eggs, milk, whipping cream, Kahlua, honey and espresso coffee powder. Cook and stir over medium heat until mixture just coats a metal spoon; do not let boil. (Should take 20 to 25 minutes and register 170 degrees F to 175 degrees F on instant-read thermometer.
Pour the hot eggnog into heatproof glasses or coffee cups. Top with whipped cream, if you like. Sprinkle each with ground cinnamon and, if you like, serve with cinnamon sticks. Serve immediately. Makes 8 (4-ounce) servings.
Prepare as above, except omit the coffee liqueur. Increase the milk to 2-1/2 cups.