First, make the praline. Lightly oil a baking tray and set aside. Tip the sugar into a heavy-based pan with 3 tbsp water and warm over a low heat until the sugar has dissolved. Turn up the heat slightly and bubble until the sugar becomes a dark caramel, about 5 mins. Remove from the heat, then stir in the nuts and a generous pinch of sea salt and immediately pour onto the prepared baking tray. Carefully spread to an even layer using a silicone spatula and leave to cool completely.

When the praline is cold and brittle, break it into rough pieces. Snap off about 10 of the caramel-coated hazelnuts and set aside. Tip the rest of the praline into a food processor and pulse to the texture of coarse breadcrumbs, then set aside.

Butter a 900g loaf tin and line with a strip of baking parchment. Melt the chocolate and butter in a heatproof bowl over a pan of simmering water, ensuring the base of the bowl doesn’t touch the water. Or, do this in the microwave in 20-second bursts. Once melted, remove from the heat and stir until glossy. In a separate bowl, whip the cream to soft peaks, then fold this through the chocolate mixture. Stir in most of the crushed praline, reserving about 4 tbsp. Scrape the mixture into the tin, smooth the surface and chill overnight until firm and set. Will keep chilled for up to two days.

Gently ease the set chocolate out of the tin onto a serving dish or board, then dust with cocoa powder and top with the reserved whole hazelnuts. Slice using a warm knife, then serve with dollops of crème fraîche and a sprinkling of the remaining crushed praline.