Extract 2 1/2 cups juice form watermelon by cutting watermelon into cubes and rubbing through a strainer to remove seeds and membrane. Sprinkle gelatin over 1 cup melon juice in a medium saucepan. Place over low heat, stirring constantly, about 5 minutes or until gelatin dissolves. Remove from heat and stir in 1/3 cup sugar, salt, remaining watermelon juice, and lemon juice.

Chill, stirring occasionally, until mixture mounds slightly when dropped from a spoon.

Beat egg whites until stiff but not dry. Gradually add remaining sugar, beating until very stiff. Fold with cream into watermelon mixture and turn into shell. Chill several hours or until set. Garnish with watermelon balls and mint sprigs. May be prepared no more than 1 day ahead.

Tip: Use a small-sized cookie or ice cream scoop to make the watermelon balls.

Serves 6 to 8.