Pre-heat the oven to 180°C/gas mark 4.
Heat the oil in a large pan and add the chopped potato, carrot, mushrooms and onion with the garlic and cook for 10 mins.
Wilt the spinach in boiling water for 2 mins, drain and pat dry.
Place all the vegetables together in a bowl and allow to cool.
Add the mince to the bowl of cooled vegetables with _ the beaten egg and season with salt and pepper. Mix it all up with your hands.
Dust a baking sheet with flour and unroll the pastry sheet on top.
Mold the mince mixture into a long sausage-like shape, place onto the middle of the pastry sheet and add a thick layer of the cranberry sauce on the top.
Brush the edges of the pastry sheet with the rest of the beaten egg.
Roll the pastry so it covers the mince mixture and squeeze the ends together.
Brush with egg and cook for 1 hour.