Cook the spinach. Drain and reserve the ½ c. of liquid.
Melt the butter in a medium saucepan, add the flour, and cook briefly until the mixture is blended but not colored. Add the shallot and cook until the shallot is translucent.
Whisk in the spinach water and the evaporated milk. Add cheese, jalapenos, and salt and pepper to taste. Cook on low heat until the cheese is melted and the mixture is combined.
Pour into a buttered gratin dish, top with panko and dot with butter.
Bake for about 45 minutes, until panko has colored.
Recipe by The Domestic Front at http://www.thedomesticfront.com/my-heart-belongs-to-daddy-creamed-spinach-with-jalapenos/