Soak porcini mushrooms in 1/4 litre of lukewarm water. Peel and finely dice onions. Heat 30 g butter in a pot and fry the onion cubes in it. Add the rice and fry well while stirring until it becomes glassy.
Deglaze with wine and let it boil down a little. Add stock and the mushrooms with the soaking water. Add the bay leaf. Let the rice swell at medium heat for about 30 minutes, stirring from time to time.
Grate the cheese finely and mix into the rice. Divide remaining butter into flakes and stir well. Season well with salt and pepper. In the meantime wash the chicken fillets, dab dry and rub with salt and pepper.
Heat the oil in a pan and fry the fillets for about 6 minutes. Arrange the risotto and chicken fillets on a large plate, removing the bay leaf. Pluck off some sage leaves, rinse, dab dry and spread over the chicken fillets.