Add sprigs of rosemary, bay leaves & thyme on top.
Chop carrotts, parsnips & sweet potatoe into large 2inch pieces & place in tray.
Add the stock so it just covers the vegetables.
Add salt & pepper with a sprinkle of olive oil, cover with aluminium foil & place in hot oven for 1hr.
Meanwhile grill sausages, leave to cool on side.
Once the vegetables have softened take tray out of oven & add the sausages & place tray back in the oven, if you're happy with the result switch the oven off & leave foil on tray as the steam will continue to cook it slowly.