Preheat the oven to 180°C.
Quarter the apples, remove the cores, peel the wedges and cut into cubes. Place the cubes in an ovenproof dish and scatter over the 10 g caster sugar and 20 g butter (cut into small pieces). Cover with foil and bake in the oven for 25 minutes.
Meanwhile, whip the cream with the rose water. In a separate bowl, fold the icing sugar into the crème fraîche. Put both in the fridge for a while.
After 25 minutes, remove the foil and bake the apples for another 5 minutes uncovered.
Mix the sea salt with the seeds scraped from a quarter of a vanilla pod. Toast the fennel seeds in a dry pan for one minute, then sprinkle in the sugar. Stir until the sugar begins to caramelise, then spread the seeds onto a sheet of baking paper to cool.
Allow the apples to cool slightly if you have time. Meanwhile, gently fold the whipped cream and sweetened crème fraîche together.