- Stir wine, sugar, vanilla bean and seeds and 300ml water in a large saucepan over medium-high heat until sugar dissolves, then bring to the boil. Squeeze excess water from gelatine, add to pan, stir to dissolve, strain (discard solids), transfer to a 2.5-litre fluted jelly mould and refrigerate until set (overnight).
- Meanwhile, for sparkling meringues, preheat oven to 100C. Whisk eggwhite and a pinch of salt in an electric mixer to soft peaks. Whisking continuously, gradually add caster sugar and whisk to firm glossy peaks. Sift over icing sugar and cornflour, fold to combine, transfer to a piping bag fitted with a 5mm fluted nozzle and pipe 2cm-diameter rosettes on oven trays lined with baking paper. Sprinkle with cachous, bake until crisp but not coloured (1-1¼ hours). Cool completely. Meringues will keep in an airtight container for a week.
- For sabayon, whisk wine, yolks and sugar continuously in a large heatproof bowl over a saucepan of simmering water until thick and pale (2-3 minutes), transfer to an electric mixer and whisk until cooled to room temperature (3-4 minutes). Fold in cream and rosewater, then refrigerate until required. Sabayon can be made up to an hour ahead of serving.
- Combine fruit and icing sugar in a bowl, toss to combine, refrigerate until required.
- To serve, dip jelly mould in hot water, then pull jelly gently away from sides of mould with your fingertips to break air vacuum. Place serving plate on top of jelly, then quickly invert and carefully remove jelly mould. Serve jelly with melon and raspberry salad, sparkling meringues and sabayon.
Note: Making a moulded jelly requires a serious amount of gelatine, which results in a firm jelly. If you prefer a more softly set jelly, reduce the gelatine by one-third and set it in a bowl instead. You’ll need to begin this recipe a day ahead.