I usually go into the butchers and say 'Can I have a joint to feed X amount of people'
However, the butcher has recently joined a website of local produce so I can order stuff and have it delivered. The only problem is I don't know what size I need.
I want to feed 5 adults - I don't mind if there are leftovers.
Do I need a 2kg or 3kg piece of topside roast?