In a large bowl, whip 1 egg with the sweet wine and 3 tablespoons of oil. Gradually add the flour (you may not need it all) until it comes together into a ball of dough. Knead for a few minutes, or until smooth and silky. Wrap in clingfilm and leave to rest for 1 hour.
Pour the sunflower oil into a large, sturdy pan on a medium-high heat, and leave it to get to 180ºC on a thermometer. Meanwhile, roll the dough into a large sausage about 4cm in diameter. Keeping the rest of the dough covered with a clean damp tea towel, slice off a ½cm-thick disc and roll into a ball, then flatten out on a flour-dusted surface to 2mm thick. Lightly dust your metal cannoli tubes with flour (or use lightly oiled dried cannelloni tubes), then wrap a circle of dough around each, sealing the edges with beaten egg. Working in batches, carefully lower into the hot oil for just 1 minute, to get lightly golden. Remove to a plate lined with kitchen paper to drain for 3 minutes, then squeeze the moulds and gently slide off the cannoli. Repeat until you’ve used up all the dough.
Melt the chocolate. Pound the hazelnuts in a pestle and mortar until fine. Drain the ricotta, then blitz in a food processor with the vanilla paste, honey, cocoa and grappa until just smooth. Spoon into a piping bag with a star nozzle, and twist the bag to give tension, then pipe the filling into the cannoli. Drizzle with chocolate, sprinkle with nuts, and serve.