In a small saucepan, combine gelatin and 2 tablespoons of heavy cream.

Allow to sit for five minutes to bloom the gelatin.

Place the pan on low heat and gently stir until the gelatin dissolves completely (about 5 minutes).

Strain the gelatin mixture through a fine sieve into the Greek yogurt and whisk until smooth.

Using an electric mixer, whip the remaining 1 cup of heavy cream until thickened.

Whisk in confectioners' sugar and rose water into the whipped cream.

Whisk 1/3 of the whipped cream into the yogurt mixture to temper it.

Gently fold in the remaining whipped cream into the yogurt mixture in two batches.

Chill the mousse for 3 hours or until set.

In a small saucepan, bring water and sugar to a boil to make a simple syrup.

Simmer until the sugar dissolves completely (about 3 minutes).

Allow the simple syrup to cool to room temperature.

Puree watermelon, lime juice, and cooled simple syrup in a blender until smooth.

Strain the watermelon puree through a fine sieve into a medium bowl.

Season the strained puree with a pinch of kosher salt and discard the solids.

Cover the bowl with plastic wrap and freeze until solid.

To serve, scrape the frozen granita with a fork to create shaved ice.

Divide the granita into eight bowls.

Top each bowl with a spoonful of rose mousse.