In a large pan, boil the potatoes, swede and carrots for 12 minutes until tender. Drain and mash.
Meanwhile, heat half a tablespoon of the oil in a frying pan and cook the onion and garlic for 5 minutes until soft.
In a bowl, mix the cooked onion and garlic mixture into the mashed potato mixture with the mustard and half the snipped chives. Add the flour and leftover beef and season with black pepper. Shape into 8 patties. Put the breadcrumbs on a plate and carefully coat the patties all over.
Preheat the oven to 160°C, fan 140°C, gas 3. Heat 1 tablespoon of the oil in the frying pan over a medium heat and cook 4 patties at a time. Cook for 3 minutes on one side, then turn them over and cook for a further 3 minutes on the other side. Use the remaining oil to cook the rest of the patties.
Transfer the cooked patties to a lined baking tray and put in the oven to keep warm.
Bring a pan of water to a simmer, and use a spoon to make a whirlpool. Crack 2 eggs, 1 at a time, into the pan and cook for 2 minutes for a runny yolk. Repeat with the other 2 eggs.
Meanwhile, boil the cabbage for 3-4 minutes, then drain. Serve 2 patties per person on a bed of cabbage, with a poached egg on top, garnished with the whole chives.