Sausage & Sweet Potato pie

1 tbsp olive oil
1 large sweet potato 
1 onion chopped finely 
2 leeks sliced thinly 
Handful of mushrooms sliced
4 sausages 
1/2 pint of chicken stock
Handful of spinach 
Handful of grated cheese

1.  Peel and slice the sweet potatoes and place in a pan, cover with water and bring to the boil. Simmer for 15 mins until soft. Mash until smooth. 

2. Melt the oil in a pan. Add the leek, onion, carrot and mushrooms to the pan and cook for 2-3 minutes. 

3. While the potato is cooking, gently remove the sausages from their skins and sliced into chunks approx and inch wide and fry in the pan until starting to brown. Pour over the chicken stock bring to a simmer for 10 minutes. Season with salt and pepper, and stir in the spinach and leave for a few minutes until it has wilted. 

4. Pour the sausage mixture into a casserole dish. Top with the potato covering all of the filling. Place the cheese on top and pop under a hot grill for 3-4 minutes until the sweet potato is starting to brown and the cheese has melted.