You can make this enchilada sauce as mild or as hot as you want, depending on how much chili powder you add. Start with a couple teaspoons of chili powder, and keep adding until you get the heat that is to your liking. Please note… this is chili powder, not cayenne powder, which is much spicier.
You can leave out the flour if you like. You will just need to reduce the broth longer to get a thicker sauce. If you are gluten-free, just use gluten-free flour.