1 Rinse lemon in hot water and remove skin with a vegetable peeler. Cut peel into thin strips. Cover and set aside. Juice lemon and measure 4 tablespoons of the juice.
2 In a pot over medium heat, heat half the champagne with 2 tablespoons lemon juice and half the sugar. Stir until sugar dissolves.
3 Mix in remaining champagne and let cool completely.
4 Pour the mixture into a baking dish and place in freezer. When the liquid begins to freeze at the edges, thoroughly stir with a whisk or fork. Freeze, stirring occasionally, for about 4 hours.
5 Halve and seed melon. Scoop out flesh with a melon baller and place in a bowl.
6 Halve vanilla bean lengthwise and scrape out the seeds. In a bowl, combine vanilla bean seeds with remaining sugar.
7 In a pot, combine white wine and 100 ml (1/3 cup) water with the vanilla sugar, lemon zest and remaining juice. Cook over medium heat for 3 minutes.
8 Let mixture cool for 5 minutes before pouring over the melon balls. Let melon balls soak in liquid at room temperature for 3-4 hours. Serve the melon balls with the granita.