Halve the peaches and remove the stones, then halve again into quarters. Heat 2 tablespoons of the sugar in a heavy-based ovenproof pan, when it begins to caramelize place the peaches, cut-side down in the caramel. Add another tablespoon of sugar on top and cook for a few minutes. As the sugar starts to disappear add 15 grams of butter and let it cook down in the sauce. Add the finely chopped basil and when the sauce is thick and syrupy, take off the heat and set to one side.
Place 250g of raspberries in a blender and puree with the icing sugar and lemon juice to taste. Push through a sieve into a bowl, using the base of a ladle and discard the seeds.
Melt the remaining butter in a wide pan until it begins to foam. Whisk the eggs, milk, cream and remaining sugar together. Scrape the seeds from the vanilla pod into the egg mixture with the finely chopped mint and mix together. Dip the brioche into the egg mixture and fry in the butter for a minute or two on each side until golden brown. Place each slice on a serving plate.
To serve, lift the peaches onto the pain perdu. Drizzle with the raspberry sauce then garnish with the basil, the remaining raspberries, a dusting of icing sugar and crème Chantilly to serve.