2 cups milk
4 ounces bittersweet (not unsweetened) or semisweet chocolate, chopped
3 2 by 1-inch orange peel strips (orange part only)
1/2 teaspoon instant espresso powder or instant coffee powder
1/8 teaspoon ground nutmeg
Combine all ingredients in heavy medium saucepan. Stir over low heat until chocolate melts. Increase heat and bring just to boil, stirring often. Remove from heat and whisk until frothy. Return to heat and bring just to a boil again. Repeat heating and whisking once again. Discard orange peel. (Can be prepared 2 hours ahead. Let stand at room temperature. Before serving, bring just to boil, remove from heat and whisk until frothy.) Pour hot chocolate into mugs.