Punch à la Romaine

Finely zest the orange (you should have about 1 tablespoon); set aside.Slice 1/4 inch off the top and bottom of the orange and set it flat on a work surface. Using a paring knife, follow the curve of the orange and slice off any remaining peel and white pith. Working over a small bowl, slice between the membranes to release the segments or supremes. (Chef Michael Symon demonstrates how to segment citrus in this CHOW Tip video.) Cover and refrigerate until ready to serve.

Place the water and sugar in a small saucepan over high heat and bring to a simmer, stirring until the sugar dissolves.

Remove from the heat and stir in the lemon zest, orange zest, and lemon juice.

Let sit at room temperature until the flavors infuse, about 30 minutes.Strain the mixture through a fine-mesh strainer into a 13-by-9-inch dish and discard the contents of the strainer. Freeze the mixture uncovered until just starting to set but not frozen completely, about 1 hour. Using the tines of a fork, rake through the mixture to break up any large chunks. Return to the freezer and rake again when thoroughly set, about 1 hour more.

Transfer the lemon ice to a container with a tightfitting lid and store in the freezer for up to 2 weeks.When ready to serve, place the egg whites in a very clean medium bowl and whisk until stiff peaks form, about 3 minutes; set aside.

Transfer the lemon ice to a large bowl.

Drizzle in the champagne and rhum agricole and stir gently to combine. Divide among 8 (1/2-cup) glasses. Divide the whipped egg whites over the lemon ice and top each serving with an orange segment.

Serve immediately.