Fry the onion in a soup spoon of butter until golden.
Add the rice and stir. Cook until the rice turns translucent.
Pour over the white wine and cook until evaporated.
Pour in small quantities of hot stock over the rice. Cook until it evaporates, stirring all the time and repeat until the rice is cooked through.
Fry the cep pieces in a pan with a large knob of butter until golden brown.
Before serving, add the chopped parsley, a knob of butter then ceps to the rice. Serve immediately.