If I want to keep the tortillas warm for a while after baking, I usually stack them as I cook them and then wrap them in aluminum foil. They’ll stay warm for a while on their own if they are wrapped in foil, but you can also put them in a 350 degree oven for a few minutes to re-warm them. However, they shouldn’t get very stiff after cooling… they won’t ever be as soft and warm as when they are freshly made, but even a day or two later, they should still be soft. If they are stiff after cooling, my guess is that they were overcooked. It’s important that the pan you cook them in be very hot – hot enough to cook them in about 30 seconds or less. If the pan isn’t hot enough, the dough will dry out too much as they cook. I also received a great tip from a reader about keeping tortillas in a cloth warmer:"I have a cloth type tortilla warmer and after cooking them they went straight into this holder to keep warm and moist for an hour. This is the ONLY warmer that keeps tortillas warm and not hard, stiff nor dried out. You can even use it in the microwave oven to rewarm the next day."