Clean and truss pheasant, reserving liver; brown pheasant and liver on all sides in butter and olive oil in a flameproof casserole. Add finely chopped carrot and onion, thyme and bay leaf. Cover casserole and simmer for 20 minutes. Pour off excess fat and flame with heated cognac. Moisten with cream; cover casserole and simmer until pheasant is tender and sauce has reduced a little.