To make the croutons tear the bread into chunks, then fry in the butter until crisp.
Bring a large pan of water to the boil. Add the broad beans and cook for 2 minutes. Add the fresh peas, sugar snaps and mangetout and cook for a further minute.
Remove from the heat, drain and stir through the spring onions.
Add the butter and sage and stir through the vegetables. Mix through the vinegar, black pepper, ham and croutons. Spoon onto a platter and serve.