Chocolate, Hazelnut and Sea Salt Tart

Some puddings are for sharing and some are for staring at. This tart is both. A dark cocoa pastry, shot through with toasted hazelnuts, holds a ganache so glossy you can almost see your reflection in it, and the whole thing is finished with crunched hazelnuts and a deliberate scatter of flaky salt. It is not a difficult tart, but it is a slow one, built in stages with a long sit at the end, and the reward is a slice that tastes like the best chocolate you have ever eaten somehow improved. The clever twist is sea salt, which does not make the tart taste salty so much as make the chocolate taste more profoundly of itself.

1 Chocolate and hazelnut, an old romance

The pairing of chocolate and hazelnut is so familiar now, thanks largely to a certain jar of spread, that it is easy to forget it was born of necessity. In Piedmont in northern Italy, chocolatiers in the early nineteenth century faced cocoa shortages and rising prices, and stretched their precious chocolate by blending it with the region’s abundant Tonda Gentile hazelnuts. The result was gianduja, a smooth chocolate-hazelnut confection that became the pride of Turin and, much later, the ancestor of every chocolate-hazelnut product on the supermarket shelf. What began as a thrifty workaround turned out to be a genuine improvement, because hazelnut’s warm, roasted sweetness rounds chocolate’s bitterness in a way few other flavours manage.

This tart leans on that history. The hazelnuts appear twice, ground into the pastry and toasted on top, so their flavour frames the chocolate from both sides. It is gianduja reimagined as a sliceable centrepiece.

2 Building the tart

There are three jobs here and none is hard, but each needs care. The pastry is enriched with ground toasted hazelnuts and cocoa, which makes it more fragile than a plain shortcrust, so chill it well and patch any cracks with offcuts rather than fretting. Blind bake it fully, because there is no further baking once the ganache goes in; an undercooked base is the one thing that will let this tart down.

The ganache is just cream and good dark chocolate, but technique matters. Heat the cream until it steams rather than boils, pour it over the chopped chocolate, and then leave it alone for a couple of minutes before stirring from the centre outwards. Beating air in or stirring too soon gives a dull, grainy result; patient stirring gives a mirror. A little butter and a spoon of honey added at the end bring extra shine and a softer, more luxurious set. Pour it into the cooled case and then, crucially, leave it at room temperature to set rather than rushing it into the fridge, which can dull the surface and firm the ganache to an unpleasantly hard chill.

3 Tips and getting ahead

Use the best dark chocolate you can, ideally around 70 per cent cocoa, because it is the entire flavour of the filling. Anything much sweeter will make the tart cloying; anything much darker can turn bitter once it sets. If your kitchen is very warm in high summer, the ganache may need a short spell in the fridge to firm up, but bring the tart back to cool room temperature before serving so the filling is silky rather than solid.

Both elements can be made ahead. The baked pastry case keeps in an airtight tin for a couple of days, and the finished tart is happy for two days under a cake dome, the flavour deepening overnight. Add the hazelnuts and salt only just before serving so they stay crunchy and the salt does not dissolve into the surface. Cut it with a hot, dry knife, wiped between slices, for clean edges.

The pastry is the only part that takes real care, so a word on it. Because it is enriched with ground nuts and cocoa, it has less stretch than ordinary shortcrust and will crack rather than drape if you rush it. Roll it between two sheets of greaseproof paper to save flouring and tearing, and if it does split as you line the tin, simply press the pieces together and patch any holes with offcuts; nobody will know once the ganache is poured. Chilling the lined case before baking sets the butter and stops the sides slumping. A small slice of this tart goes a long way, so a single one genuinely serves a crowd, and a spoonful of creme fraiche or a few fresh raspberries alongside cuts the richness beautifully if anyone needs rescuing.