Place the ham hock in a pot and cover with cold water. Add the onions and celery and bring to the boil. Simmer until fork tender. Alternatively put in a pot, cover with a lid and bake in a 160oc ...

Add the garlic and soup celery if using and cook for 5 minutes. Mix into the lentils with the ham hock. Whisk the mustard, honey and vinegar together. Whisk in the oil and check seasoning.