- Preheat the oven to 190C/Gas Mark 5.
- To make the onion gravy melt the butter in a pan, add the onions and cook gently for 5 minutes until soft. Sprinkle over the sugar and cook for a further 15 minutes over a low heat until the onions are caramelised and golden. Add remaining gravy ingredients and simmer for 5 minutes until the gravy thickens.
- Meanwhile cook potatoes in boiling water for 20 minutes until tender.
- Place the Quorn Sausages on a baking tray and lightly brush with oil then cook for 14 minutes (reduce the time to 12 minutes for fan assisted ovens). When cooked slice each Quorn Sausage into three equal pieces and add to the onion gravy then transfer to an oven proof dish.
- To finish the Colcannon mash, drain the potatoes into a colander then melt the butter in the same pan and stir-fry the leek and cabbage for 5 minutes, season with black pepper. Return the potatoes to the pan with the leek and cabbage and 3 tbsp milk. Mash until smooth and check seasoning.
- Top the pie with the mash and return to the oven for about 15 minutes until the topping is golden and the filling is piping hot.
Tip - as an alternative try topping with a cauliflower or sweet potato mash.