Boil 1 liters of water, stir in the stock. Peel and finely dice the onion. Heat the oil in a saucepan and sauté the onion until translucent. Add rice and sauté briefly.
Pour the 2nd half of the stock into the rice, bring to the boil and cook covered over low heat for about 20 minutes. When the liquid has been absorbed, gradually pour in the rest of the broth, stirring occasionally. If you want, you can add a shot of wine!
Clean the mushrooms, cut into slices and thinly slice the ham. Heat the butter in a pan, fry the mushrooms in it. Season with salt and pepper. Add the ham.
Add the mushrooms, ham and then the peas to the risotto about 5 minutes before the end of the cooking time. Wash and finely chop the parsley and fold into the risotto. Garnish with a little parsley.