|Onion||1 , chopped|
|Carrot||1 , chopped|
|Chicken stock/Veal stock||125 Milliliter (1/2 Cup)|
|Ground black pepper||To Taste|
Preheat the oven to 350°F (180°C).
Keep the lettuces whole, wash them well and trim the base as neatly as possible without detaching any leaves.
Blanch the lettuces in boiling salted water for 5 minutes.
Drain them and put into a bowl of cold water at once.
Drain again, squeezing the lettuce to remove any excess moisture.
Grease a large ovenproof casserole with the butter.
Line the bottom of the casserole with the bacon.
Cover the bacon with the onion and carrot and lay the lettuce heads on top.
Pour in the stock, season well and add the bouquet garni.
Lay a piece of buttered waxed paper on top of the lettuce heads, cover the casserole and put into the oven for 45 minutes.
Lift out the lettuce heads, arrange them in a warm serving dish and keep warm.
Put the casserole over high heat and boil the cooking liquid for 5 to 10 minutes or until it is well reduced.
Strain the liquid over the lettuce and serve.