Add the flour and stir until mixed in and it forms a ball of dough.
Add milk slowly, mixing in between to make sure it gets well mixed in before adding another lot. Stop adding when it gets to the consistency of thick cream.
Add about ¾ cup grated cheese and heat to melt.
Season to taste.
To assemble
Oil a baking dish.
Place half the spinach on the bottom.
Cover with all the meat mixture.
Place slices of cheese on top.
Add the rest of the spinach.
Pour the white sauce over the top.
Place in the oven until the top is browned.
Recipe by The Low Fodmap Diet at https://www.strandsofmylife.com/find-toilets-travelling-spinach-mince-pasticcio/