Soak the kidney in warm salted water for 30 minutes.

Wash the mushrooms, peel and cut into pieces. Chop the stalks finely.

Cut the kidney into small pieces, removing the hard core and fat.

Peel and chop the onion.

Heat the fat in a big saucepan.

Fry the onion, kidney, and mushrooms for five minutes, turning to cook evenly.

Push the ingredients to one side of the saucepan.

Stir in the flour and seasonings.

Stir in half of the stock and stir until it boils.

Cover and simmer gently for 45 minutes.

Add the well-washed rice and the remaining stock.

Continue to simmer gently for 12 to 15 minutes more, or until the rice is tender.

Skim if necessary.

Serve hot.