When it bubbles, stir in an oz. of flour and cook for 2 minutes earlier than steadily whisking in ¼ pint of milk. Thin the sauce to an appropriate consistency with some lamb inventory from the pot and let it simmer for no less than 10 minutes, adding more inventory if it will get too thick. Stir within the chopped mind and some parsley if you wish. Season and add a squeeze of lemon juice. As mentioned earlier, essentially the most fundamental distinction between lamb and mutton is age.