In a small bowl, sprinkle gelatin over water and allow to soak for 5 minutes.
Wash, dry, and zest the clementines, set the zest aside.
Chop the clementines. Remove any visible seeds, puree clementines with champagne until smoothish.
Press clementine pulp through a wire sieve, into a clean bowl or measuring cup.
Measure out 1 cup of puree. If you don’t have enough, repeat with another clementine.
Combine the measured clementine puree with sugar and zest, set aside.
Transfer gelatin bowl to microwave, heat in 10 second increments until gelatin is completely melted.
Pour melted gelatin into orange mixture, stir until well incorporated, then set aside while preparing the remaining ingredients.
In a separate bowl (stand mixer, ideally!), whip egg whites until stiff peaks form. Add on top of orange mixture, set aside.
Whip heavy cream until stiff peaks form, then carefully fold in to the fruit mixture along with the egg whites, gently folding until combined.
Pour into 4 serving glasses, chill until set, about 2 hours.