- Heat the oil in a large frying-pan and brown the meat well. Remove to a saucepan.
- Sauté half the onion in the frying-pan with the leeks, carrots and celery. Add to the meat along with the garlic. Pour in the stock and stout, then season. Simmer gently for approximately 1½ hours. Remove the meat from the pot. Strain the liquid into a clean saucepan. Discard the vegetables.
- Place the meat into the saucepan containing the strained cooking liquid.
- In a frying-pan, heat 25 g (1 oz) of the butter and sauté the bacon, mushrooms and remaining onions. Add the mixture to the meat in the saucepan and reheat.
- Blend the flour with remaining butter. Add it into the sauce, stirring well for a few minutes to blend. Check seasoning, then serve in a deep dish with buttery mashed potatoes.