The only slight disadvantage to preparing this dish is the patience needed to peel these delicate beans, but the end result is well worth the effort. (When not in season, most chefs, myself included, are happy to use frozen broad beans. The quality is good as they are picked, shelled and frozen over a very short period to ensure none of the flavour is lost.)
Bring a large pan of water to the boil, add the broad beans and simmer for 5 minutes. Drain them and peel off the skins, then set aside.
Heat the butter in a pan, add the garlic and shallots and sweat for 5 minutes. Add the salsify, pour in the stock and cream and bring to the boil. Reduce the heat and simmer for 12-15 minutes or until the salsify are tender. Remove the salsify with a slotted spoon and boil the cooking liquid until reduced and slightly thickened. Stir in the mint and lemon juice and season to taste. Return the salsify to the sauce with the broad beans, reheat gently and serve.