Easiest is in a nonstick pan on the stove. Covered or not, try both to see how you like it best. This maintains crispness on the bottom. Covering it or not determines how hot the toppings get in relation to the bottom. Bonus - often a pizza is undercooked on the bottom. Heating this way uncovered can finish cooking the bottom crust.
I put the pizza stone on the top shelf of the oven and turn the broiler on high. Using a infrared thermometer, when the stone is at approximately 700 degrees, I move the stone to the bottom shelf. Then set the broiler to low and throw the pizza on the stone. Check it at 2 minutes and if necessary, let it go one more minute. Perfect crispy thin crust pizza. YMMV
@BadTouchRobot This seems like the best method, except I don’t have a pizza stone. Might try it with a baking sheet, though. I’ve eaten leftover pizza cold forever, but I’ve kind of lost my fondness for it recently.
Depending on the pizza and how hungry one is. Good pizza could be eaten cold for breakfast. Now for lunch or dinner in the microwave if I’m really hungry. If I can hold off I’ll use the counter top all in one appliance that takes time to preheat.
I really like cold pizza as a snack, but it if I want it to feel like a meal again:
Skillet is my low-hassle fave, if I can spare a few minutes.
Toaster oven if in a hurry (most often).
If I have more time than hunger, and want the best reheat possible, I put it on the sandwich press.
Ours can do separate temps above and below, and the plates can be locked at different heights, so I can get the top one juuust over the cheese-side without touching it. Dialing in my temps I can get the crust perfect again and doesn’t over nor under heat the cheese. The reheating process itself is actually quite fast, it’s the hassle of getting the sandwich press out that I like to avoid. I only bother with this when we’ve bought really good stuff.
Our local (good, not chain) pizza place gave us the best process: Use a frying pan, heat it to “high”, put the pizza slices in and turn down to “low.” Cover and leave it in until the cheese is melted, 8-10 minutes. Perfect – crust is crunchy, toppings are heated through. I like to leave it in just a bit longer until the cheese melts enough to overflow to the pan a bit, offering a treat that our family calls “cheese crusties.” (This is for a medium crust style, not deep dish or thin crust. The same process works, but adjust the time accordingly.)
The best leftover pizza I’ve ever had was when I worked at a pizza shop. It was left in the box and set atop the pizza oven as it cooled down overnight. It was dried out on the outside from from the dissipating heat of the oven overnight, but not enough that the inside was overcooked. So I guess that’s similar to air-frying?
depends on the pizza. thin, foldable style pizza can be eaten cold. chicago style or grandma sicilian style goes in the oven in a foil lined deep dish pan - 15 minutes covered with foil then 15 minutes uncovered at 350.
if you have something in between, a cast iron pan is great but any heavy sauté pan will do (for even heating). put the slice(s) in, foil down over top (over the slice not over the pan, but gently so the toppings don’t stick to it) and heat gently until the cheese is melty again then remove foil to finish crisping the bottom.
As someone who remembers when microwave ovens were not a common sight in the kitchen, I still regard them as a technological wonder, but they are an abject failure at satisfactorily heating up leftover pizza.
Any of the other options are fine, but toaster oven is my preferred go-to. A regular oven at low temperature will serve in pinch.