Spanish ham croquetts

1) Heat the olive oil in a large frying pan over medium heat.
2) Add the flour and cook for 3 minutes, stirring constantly, until a smooth paste forms.
3) Slowly add the milk and chicken stock, stirring constantly, until well combined.
4) Add the nutmeg, and salt and pepper to taste.
5) Cook over medium heat, stirring constantly until the mixture is thick and smooth and starts to pull away from the sides of the pan.
6) Lower the heat to low. Add the minced ham, stirring constantly until well combined.
7) Put the mixture into a dish and refrigerate until the mixture is cold, about 2 hours.
8) Pour the breadcrumbs onto a plate.
9) Take a walnut sized piece of the ham mixture, roll into a ball and dip in the egg, then coat with breadcrumbs and put onto a plate. Continue until they are all ready.
10) If you are entertaining you can do this earlier and leave them in the fridge until you are ready to fry them.
11) Add about 1/2-inch oil to a large frying pan and heat to 180°C.
12) Fry the croquettes in batches, turning until golden.
13) Remove the croquettes with a slotted spoon to a plate lined with kitchen roll. Serve immediately.