- Heat milk in saucepan until hot and set aside.
- Melt butter in a large fry pan.
- Add flour and blend into roux.
- Add hot milk and cook and stir until creamy - at least 5 minutes.
- Thin with water if sauce becomes too thick.
- Add chiles, jalapenos, salt, pepper and garlic powder.
- Stir until blended then set aside.
- In separate pan saute onions in olive oil until onions are translucent.
- Add spinach and cook 5 to 10 minutes.
- Stir 1 cup of sauce into spinach mixture.
- Reserve ½ pound Swiss cheese for topping and divide remaining cheese into 10 parts.
- Put a portion of cheese on a tortilla, top with about ½ cup of the spinach mixture and more cheese on top of spinach.
- Roll tortilla, tuck ends underneath and place on a baking pan.
- Continue until all are gone.
- Cover each tortilla with a ladle of sauce and sprinkle reserved cheese on top.
- Bake in a preheated 375°F oven 15 to 20 minutes or until golden brown.
- Serve with extra sauce.