This dish, made with canned chile peppers is very mild. I prefer roasted Hatch Green Chile's which I can purchase in our local grocery store, they have delicious flavor but are still very mild, even for spice wimps like me! If you want to kick up the spice in your dish, try using pepper jack cheese, adding a few (or a lot) of shakes of Tabasco or Cholula sauce to the milk and egg mixture. Plus Hatch chiles are from New Mexico, making this a truly authentic New Mexico chile relleno casserole recipe.