Place the hazelnuts on a baking tray and bake for 5–10 minutes, until toasted and light brown, then finely grind in a food processor.
Melt the butter gently in a saucepan. Brush 8 cappuccino cups, or 150ml cups or ramekins with a little of the butter, then dust them with some of the ground hazelnuts. Tap out any extra nuts and set aside with the remaining nuts and pan of butter.
Sieve the flour into a bowl with a pinch of salt, then carefully mix with the almonds, sugar, eggs and egg yolks, zest and milk.
Using a knife, scrape out the seeds from the vanilla pod. Add to the mixture, along with the set aside hazelnuts. Fold in the butter and the orange juice. Divide among the cups, then poke the pieces of chocolate into the middle of each.
Place the cups on a tray and bake for 15 minutes, until risen but not quite cooked through in the middle. This will make them moist and delicious!
Serve hot with an extra sprinkling of hazelnuts, if you like, and a blob of crème fraîche.