Set the oven at 190c/gas mark 5. Peel the onions and slice them in half from root to tip, then cut each half into about 6 or 8 pieces. Soften them slowly in a flameproof baking dish or roasting tin, in a tablespoon or so of oil over a moderate heat. While they are softening, peel the parsnips and cut into short, thick chunks, about the length of a wine cork. Add them to the onions and leave to colour, turning up the heat a little if needs be.
Cut each sausage into three and add to the pan. Cut the black pudding into thick slices then cook them with the other ingredients till they are golden on the outside. It is important everything is a good colour. Strip the leaves from the thyme and stir them in together with the chicken stock. Bring to the boil briefly, then put in the oven to bake for 30-40 minutes, until the parsnips are truly tender and the stock has reduced to a syrupy glaze. Serves 2.
2 medium onions
2 very large or medium parsnips
4 plump butcher's sausages
250g black pudding
a few sprigs of thyme
250ml chicken stock