To make the herb mash: cook potatoes in boiling water for 10 minutes or until soft. Drain and mash with butter, cream, McCormick Mixed Herbs, Chives and Salt. Cover and set aside. Keep warm.
Cook the sausages in a large frying pan with the oil over medium heat for 8 minutes or until cooked. Remove to a plate, cover and set aside. Keep warm.
Using the same pan you cooked sausages in add the onions and cook until soft over a medium heat then stir in mustard, flour and stock to make a smooth sauce.