Heat over 400. Combine flour and butter to make rue. Stir constantly, whisk in milk and bring to a boil. Seasonwith salt, pepper and cayenne. Simmer for 5 to 6 minutes or until rue coats the back of a spoon. Remove from heat and stirin the cheeses,
In a sauce pan heat the oil, add the onions and saute for 2 minutes, stir in spinach, garlic and artichokes and saute for 2 minutes. Add salt and cayenne pepper. Remove from heat and fold into the cheese sauce. Bake for 10 to 15 minutes or until the top is brown.