Raspberry and Chocolate Torte

STEP 1: GRIND THE PECAN FLOUR

Combine the pecan halves and icing sugar in a food processor and pulse in short bursts, scraping down twice, until you have a fine, dry, sandy flour - about 45 seconds of pulsing in total. The sugar absorbs the oil the nuts release and stops the mixture climbing into a paste, so stop while it is still loose and free-flowing. Sift with the cocoa powder, cornflour and salt, tipping back in any large pieces left in the sieve.

STEP 2: MAKE THE SPONGE

Heat the oven to 170C / 150C fan / 340F. Line the base of the springform tin and grease the sides. Melt the 70% dark chocolate with the butter over a pan of barely simmering water, stir smooth and leave to cool to just above body temperature. Whisk in the egg yolks one at a time. In a clean bowl whisk the egg whites to soft peaks, add the caster sugar in three additions and whisk to a firm, glossy meringue. Fold a third of the meringue into the chocolate base to slacken it, then alternate the remaining meringue with the pecan mixture in two further additions, folding with a large metal spoon and stopping the moment no dry pockets remain. Bake for 30-35 minutes, until the top has set with a papery crust and a skewer inserted 2 cm from the edge comes out with a few moist crumbs; the centre will still be soft. Cool completely in the tin - the sponge will sink slightly and that is correct.

STEP 3: MAKE THE CHOCOLATE CREMEUX

Soak the leaf gelatine in cold water. Bring the milk and cream to just below a simmer. Whisk the egg yolks with the caster sugar and salt, pour on a third of the hot liquid whisking constantly, then return everything to the pan and cook over a low heat, stirring with a spatula in a figure of eight, until it reaches 82-84C and coats the back of the spatula. Take it straight off the heat, squeeze the gelatine and stir it in until dissolved, then pour the hot custard through a sieve onto the chopped 64% dark chocolate. Wait 60 seconds, then stir from the centre outward until glossy and emulsified, blending with a stick blender if you have one. Cover with cling film touching the surface and chill for at least 3 hours, until firm enough to hold a piped line.

STEP 4: TEMPER THE CHOCOLATE AND PIPE THE LEAVES

Melt two thirds of the 55% dark chocolate to 45-50C, add the remaining third off the heat and stir until it drops to 27C, then warm gently back to 31-32C. Work in a cool room; if your kitchen is above 22C, do this late in the evening. Pipe the leaves onto a sheet of acetate with the leaf nozzle, drawing each one in a single confident stroke, then drape the sheet gently over a rolling pin so they set with a natural curve. Reserve 100 g of the tempered chocolate and spread it in a thin band along an acetate strip for the collar. Leave everything to set at cool room temperature, not in the fridge.

STEP 5: WHIP THE RASPBERRY CHANTILLY

Whisk the mascarpone briefly to loosen it, then add the cold double cream, icing sugar, freeze-dried raspberry powder and vanilla bean paste and whisk to firm peaks. It will take less time than plain cream and will over-whip faster, so stop while the whisk still leaves a clean, standing ridge. Keep it refrigerated until the moment it goes into the torte.

STEP 6: ASSEMBLE AND FREEZE

Slice the cooled sponge horizontally into two even layers. Return the base layer to the springform tin and line the inside of the ring with a 6 cm acetate collar so it sits flush against the tin wall. Warm the raspberry jam with the lemon juice and brush it over the base layer, then press 250 g of the raspberries into the jam, hollow side down, in a single close layer. Beat the chilled cremeux briefly to loosen it and spread half over the raspberries, working it right out to the acetate so there are no voids at the edge. Add the second sponge layer, press gently, spread the raspberry chantilly over it and top with the remaining cremeux, levelling with an offset palette knife. Freeze the whole assembly, uncovered, for 1 hour. This hour is the single most important instruction in the recipe.

STEP 7: GLAZE, DECORATE AND SERVE

Warm the double cream with the liquid glucose, pour it over the remaining 100 g of chocolate and stir to a smooth, glossy glaze; let it cool to about 30C. Release the springform and peel the acetate collar away from the frozen torte - the sides will come away sheer and glassy. Pour the glaze over the top and coax it just to the edge with the palette knife, letting a few deliberate drips run down. Arrange the remaining 100 g of raspberries and the piped chocolate leaves on top while the glaze is still tacky. Transfer to the fridge for 45 minutes before serving to bring the interior back from frozen to cold-set, then cut with a long thin knife warmed under hot water and wiped dry between every slice.