Heat the oven to 180°C/fan 160°C/gas mark 4, put the hazelnuts on a baking sheet and toast for about 5-6 minutes (be careful not to burn them!).
Blitz the hazelnuts in a food processor or mini chopper to finely chop.
Drain and mash the cannellini beans with a fork or use the processor.
Pace the nuts, cannellini beans, ricotta, oregano, lemon zest and 100g of the grated cheese into a bowl. Season with black pepper and mix well.
Using your hands shape the mixture into 16 small balls.
If you are freezing any of the balls, this is the time to do it. Otherwise, heat 1-2 tbsp olive oil in a frying pan and fry the balls gently. Turn them carefully because they do soften up as they cook. You don't need to cook them through because they will finish cooking in the oven; you just want to get some colour on them.