Place beef mince in a large, deep frypan. Cook over medium high heat until evenly brown. Drain, crumble very finely and set aside.
In a food processor, chop the carrots, onion and ham.
Melt butter in a large saucepan over low heat. Stir in carrot mixture and simmer for 3 to 5 minutes. Stir in cooked beef, beef stock, tomato paste, lemon zest, bay leaves, basil and nutmeg. Simmer over lowest heat, partially covered, for at least 2 hours, stirring occasionally.
Immediately before serving, stir in cream and mix well.