Combine first 5 ingredients in heavy medium saucepan. Cook over medium heat, whisking often, 3 to 4 minutes or until chocolate is melted. Increase heat to medium-high, and cook, whisking often, 4 to 5 minutes or just until mixture begins to boil. Remove from heat; discard orange rind strips. Serve immediately with sweetened whipped cream. Garnish, if desired.
Orange-Scented Mocha Sipping Dessert: Prepare recipe as directed, decreasing milk to 2 cups and stirring in 1 cup half-and-half with milk and remaining ingredients.
Note: Both of these recipes can be prepared up to 2 hours ahead. Let stand at room temperature. Before serving, bring to a light boil, whisking occasionally; remove from heat, and serve immediately.