Paris-Brest with hazelnut praline cream

Toast the hazelnuts at 170°C (150°C fan) for 10 minutes, until golden.

Melt the sugar in a pan to a deep amber caramel. Stir in the warm nuts, pour onto a lined tray and leave to harden.

Break up and blend in a food processor for 5 to 8 minutes, scraping down often, until it turns into a smooth, runny paste.

Heat the oven to 190°C (170°C fan). Draw a 20 cm circle on baking paper and turn it over on a tray.

Bring the water, milk, butter, sugar and salt to the boil. Add the flour all at once and beat over the heat for 1 to 2 minutes, until the dough comes away from the pan and leaves a film on the base.

Cool for 3 minutes, then beat in the egg a little at a time until the dough is glossy and falls from the spoon in a V shape. You may not need all of it.

With a 1.5 cm star nozzle, pipe two touching rings along the circle, then a third on top over the join. Brush with egg wash and scatter with almonds.

Bake for 40 to 45 minutes without opening the door for the first 30. Turn the oven off and leave the ring inside, door ajar, for 10 minutes to dry out.

Heat the milk. Whisk the yolks, sugar and cornflour, pour on the hot milk while whisking, then return to the pan.

Whisk over medium heat until it boils, and cook for 1 minute more. Off the heat, whisk in 60 g of the butter. Cover the surface and chill until cold.

Let the cream and the rest of the butter come to the same cool room temperature. Beat the butter until fluffy, then beat in the cream a spoonful at a time, and finally the praline paste.

Slice the ring in half horizontally. Pipe the mousseline generously onto the base in rosettes, put the top on and dust with icing sugar.

Chill for 30 minutes to firm up, then serve the same day.