In a pot large enough to fit all the ingredients place the milk, onions, and mace. Bring to a boil, reduce to a simmer, and cook for 20 minutes.

Then add the tripe and season cautiously with salt and pepper (you can add more later). Bring up to a gentle boil, reduce again to a simmer, and cook for a further 45 minutes to 1 hour, checking the tripe’s giving qualities with a sharp knife. Be careful, as if cooked too long tripe will just melt away.

Now, in another pan, melt the butter and add the flour. Cook this, stirring to avoid browning, until it smells biscuity. Continue stirring vigorously (a whisk might be useful here) and add a couple of ladles of the liquor from the tripe pot. Once thoroughly mixed and smooth, return this mixture to the tripe. Stir in thoroughly and simmer for a further 15 minutes to allow the dish to thicken slightly. Adjust the seasoning to taste and serve hot, using a slotted spoon, with mashed potatoes.