Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3). Peel and chop the onion. Clean, wash and, depending on size, halve or quarter the mushrooms. Dab meat dry and cut into cubes.
Heat clarified butter in a wide saucepan. Fry the meat for about 5 minutes. Season with salt and pepper and remove. Fry onion and mushrooms in hot frying fat for about 5 minutes. Add meat again.
Dust with flour and sweat briefly. Deglaze with wine, stock and cream. Bring everything to the boil and simmer for about 10 minutes.
Bake the pies for 5-10 minutes. Wash the chervil, put some aside and chop the rest. Heat the peas in the ragout. Season the ragout with Worcester sauce, salt and pepper. Add chervil. Fill the pies with the ragout.
Garnish with remaining chervil.