In a deep pan add water, tomatillos, onion, cilantro, salt and garlic. Cook until it boils for 5 minutes. Remove from heat and let cool for additional 5 minutes.
Pour everything from the pan into a blender and blend well.
Next, add the avocado, sour cream and tbsp of cilantro. Blend until creamy.
In a separate flat pan, add oil, tablespoon chopped onion, shredded cheese and 2 oz of the tomatillo sauce from blender. Cook for 2-3 minutes. Add spinach, continuous stir until it is dark green. Set aside.
First warm the tortillas with a little canola oil. Lay the warmed tortilla flat in a casserole pan and add 3 ounce of spinach mixture down the middle. Roll the tortilla and cover with the sauce you just made. Add a little cheese down the center on top of the tortilla and bake in preheated over (350 degrees) for several minutes until cheese is melted.
Serve with Spanish rice, slices of avocado and a touch of sour cream.