Cook the spinach. Drain, reserving one cup of liquid, and chop fine. Melt the butter in a saucepan and add the flour. Blend and cook a little. Do not brown. Add onion and garlic. Add one cup of spinach liquid slowly, then add evaporated milk, black pepper, celery salt, and cheese. Add one or more jalapeño peppers (how many is a question of taste as well as what kind. Colwin used the pickled kind, from a jar. I used one fresh), and the spinach. Cook until all is blended. Turn into a buttered casserole topped with buttered bread crumbs, and bake for about 45 minutes at 300° F until the top is crisp and golden. If you want to speed up the browning, toast under the broiler.