Defrost the peas. Drain asparagus and cut into small pieces. Peel and finely chop the onion. Quarter the sausage lengthwise and cut into slices. Heat the pâté in a preheated oven (electric cooker: 200 °C/ gas: level 3) for 8-10 minutes. Sauté onion in hot fat.
Add meat sausage and fry while turning. Deglaze with cream and stock, bring to the boil and sprinkle with sauce thickener. Season to taste with salt, pepper and lemon juice. Heat the asparagus and peas in it. Pour the ragout into the pies. Sprinkle with chervil and serve garnished with lemon