Chocolate Hazelnut Tart

In a large bowl, whisk together the all-purpose flour, cocoa powder, 100g white sugar, and a pinch of salt. Add the 120g cold butter, cut into cubes, and work with your fingertips or a pastry cutter until the mixture resembles coarse, sandy crumbs — no large butter pieces remain.

Crack the egg into the bowl and stir with a fork until the dough just comes together. Turn onto a lightly floured surface, press into a flat disc, wrap in plastic, and refrigerate for 30 minutes.

Preheat your oven to 180°C. On a lightly floured surface, roll the chilled dough to about 3mm thick and line a 24cm tart tin, pressing gently into the edges. Trim any overhang. Prick the base all over with a fork, line with parchment and pie weights, and blind bake for 18-20 minutes until the edges are set. Remove the weights and bake a further 5 minutes until the base looks dry and faintly toasted. Set aside to cool slightly.

Spread the hazelnuts on a baking sheet and toast in the oven at 180°C for 8-10 minutes, until the skins are loosened and the nuts smell fragrant. Wrap them in a clean kitchen towel and rub vigorously to remove most of the skins. Let cool completely, then roughly chop and set aside.

Coarsely chop the dark chocolate and place in a heatproof bowl. In a small saucepan over medium-low heat, warm the heavy cream and remaining 50g butter, stirring occasionally, until it just begins to steam and tiny bubbles appear around the edges — do not boil.

Pour the hot cream mixture over the chopped dark chocolate. Let it sit, undisturbed, for 2 minutes. Then stir gently from the centre outward with a spatula until the chocolate is fully melted and the mixture is smooth and glossy.

Whisk 80g white sugar, the vanilla extract, and the 2 whole eggs directly into the chocolate cream mixture, whisking gently until the filling is homogenous and slightly thickened. Do not over-whisk or incorporate too much air.

Scatter the chopped toasted hazelnuts evenly across the pre-baked tart shell. Slowly pour the chocolate filling over the hazelnuts, letting it settle naturally.

Bake the tart at 160°C for 20-22 minutes. The filling should be set at the edges but still have a very gentle, barely-liquid wobble in the centre when you nudge the tin. A skewer inserted 2cm from the edge should come out with just a trace of moist chocolate.

Remove from the oven and allow the tart to cool in the tin on a wire rack for at least 60 minutes. The filling will firm up as it cools. Do not refrigerate — serve at room temperature for the best texture and flavour.

Dust the cooled tart generously with the remaining cocoa powder through a fine-mesh sieve just before serving. Slice with a warm, dry knife, wiping between cuts, for clean portions. Serve at room temperature on its own or with a small quenelle of vanilla gelato alongside, if you like.