Method

1. Peel & cube potatoes & carrot, boil to soften (just par-boil, give them a head start)
2. Melt butter in a large pot/pan and cook onions, leeks and mushrooms for approx 10 mins until soft but not brown
3. Add herbs and stock and bring to a simmer
4. Mix cornflour to a smooth paste with a little of the milk. Add to the pan with remaining milk and stir over heat until lightly thickened. Season generously.
5. Mix potato, carrot, spinach & peas through.
6. Grease pie dish with butter, then line pie dish with pastry.
7. Pour in pie contents. Sprinkle grated cheese on top.
8. Top with pastry, crimping the edges closed. Lightly glaze with some egg white or milk.