Whisk in 3 tbsp of all-purpose flour & cook until bubbly (about 3 minutes).
Stir in 1 cup of seafood stock & 2 1/2 cups of milk.
Bring to a boil, stirring constantly. Remove from the heat & add seasonings (salt, pepper, cilantro, etc). Let it cool.
In a large bowl add 2 cups of any seafood, chopped & cooked. (firm fish, shrimp, crab, lobster, etc.). Whatever you have, whatever you want.
Stir in 1/2 cup of the cooled sauce & 1/2 cup of shredded Monterey Jack cheese.
In a 6 inch corn tortilla spread a thin layer of sauce & 4 tbsp of filling down the center.
Roll it up & place seam side down in a 9 x 13 inch baking dish coated with cooking spray.
Repeat this with 11 more tortillas. Spread the remaining sauce over the top & sprinkle 1 1/2 cups of Monterey Jack cheese over it.
Bake at 350 about 40 minutes or until hot & bubbly.