Place the chicken, stock cube, onion and mushrooms into a pan.
Add the water so it just covers all the ingredients; so use a small pan if possible.
Bring to the boil, then turn down and simmer for 30 minutes, or until the meat falls apart.
Once cooked, strain in a colander and then measure back to about 600mls.
Place the stock back into the pan and bring to the boil.
Mix the flour and water together well, then whisk into the simmering stock until it thickens and boils. Remove from the heat.
Pull the chicken apart not too small pieces. Place into 4 ovenproof deep bowls.
Add the onions and mushrooms in equal amounts in the bowls.
Then add the cooked broccoli and then pour over the thickened sauce evenly, leaving a 2cm gap from the top of the bowl.
Roll out the puff pastry 1/4 cm thick and cut large squares, making sure you leave a large over hang on the bowls.
Brush the rim of the each bowl with beaten egg.
Lay the pastry over and seal well, brush with beaten egg and make a small incision in the top.
Bake in the pre heated oven on a tray for 20 minutes until well risen and browned.
Meanwhile, heat the oil and sauté the potatoes until lightly browned, then add spinach and wilt slightly so they cover the potatoes, season well with salt and pepper and serve with the pies.