Place the silverside into a large pot and cover with cold water. Add the onion, bay leaves, peppercorns and garlic.
Bring to a gentle simmer, skim any foam from the surface, then reduce the heat and cook gently for around 2½ to 3 hours until tender.
About 30 minutes before the silverside is ready, boil the potatoes until soft. Drain well, then mash with the butter and milk until smooth and creamy.
Steam or boil the cabbage for 5 minutes until just tender. Toss with the extra butter and season to taste.
Remove the silverside from the cooking liquid and allow it to rest for 10 minutes before slicing across the grain.
Serve with the creamy mashed potato, buttered cabbage and a little chopped parsley.
Notes
For an extra traditional meal, serve with wholegrain mustard or your favourite white sauce. Leftover silverside is also perfect for sandwiches the next day.