Fry the onion in the butter for 3 mins. Add the tomatoes, lemon juice, half the vinegar, the tomato purée, Worcestershire sauce, brown sugar, stock, parsley, and salt and pepper to taste. Bring to the boil and simmer gently for 20 mins until fairly thick. Keep the sauce warm.
Lightly toast and butter the crumpets or muffins, and keep them warm. Half fill a deep frying pan with water. Add the rest of the vinegar, and bring to a gentle rolling boil. One at a time, crack each egg into a cup, and slide the egg into the bubbling water.
Poach the eggs for 3 mins. Using two spoons, gather in the egg whites as they start to set, to give each egg a neat shape. Lift out the cooked eggs and drain on kitchen paper. Put each crumpet or muffin on a plate, and top with an egg. Spoon over the hot sauce, and serve immediately.
Servings: 8