| 1 | You may get 2 or 3 large hearts for this weight or several smaller ones. |
| 2 | Whatever the size, they will be slashed; this is normal. |
| 3 | Wash the hearts and trim away waste - fat, membrane, gristle and arteries. |
| 4 | Soak in lightly salted water for 10 minutes then rinse, drain and dry well. |
| 5 | Chop the onion finely and soften it in 1 oz butter. |
| 6 | Away from the heat stir in the breadcrumbs, lemon zest, 4 tablespoons parsley and lots of salt and pepper. |
| 7 | Bind with the egg and milk. |
| 8 | Use the mixture to stuff the heart cavities, and secure the openings with toothpicks or cocktail sticks - there is no need to make perfect closures. |
| 9 | Whizz the tomatoes in a blender, stir in the vinegar and add enough stock to make up to 1 pint. |
| 10 | Dust the hearts thoroughly with the well-seasoned flour. |
| 11 | Melt 1 oz butter in a flameproof casserole, stir in the leftover flour and let it brown a little. |
| 12 | Blend in the tomato mixture and make a smooth, bubbling hot sauce. |
| 13 | Lay the prepared hearts in the sauce and tuck the bay leaves among them. |
| 14 | Cover with greaseproof paper and the lid, and cook at 325°F (160 c) gas mark 3 for 1 hour. |
| 15 | Turn the hearts gently and continue cooking for 1 to 1-?hours more until meat is beautifully tender. |
| 16 | Transfer the hearts to a warmed serving dish. |
| 17 | Stir the mustard into the sauce, add salt and pepper to taste - and carefully blend in the yoghurt if liked. |
| 18 | Pour the sauce over the hearts, scatter lavishly with chopped parsley and serve with boiled potatoes or noodles. |
