Preheat the oven to 180 degrees centigrade. Heat the oil in a large frying pan and quickly brown the lamb cutlets for 2 minutes on each side. Remove from the pan and transfer to a 2 litre casserole dish.
Add the onion and garlic to the pan and cook for 3-4 minutes until softened and golden. Add the the tomatoes, herbs, sugar, vinegar and lamb stock and simmer together for 2-3 minutes. Add salt and pepper to taste.
Empty the beans over the lamb cutlets then roughly stir in the tomato mixture. Sprinkle the breadcrumbs on top of the casserole in an even layer, cover and bake for 30 minutes. Remove the cover and cook for a further 30 minutes until bubbling and golden brown on top.