Open the can of yams and drain them. Make sure to reserve the liquid.
If using the oven preheat to 350 degrees.
Put the yams in an oven safe container. If you are using an air fryer make sure it fits inside the air fryer.
Heat the butter, brown sugar, cinnamon, nutmeg, salt and yam juice in a pan over medium heat.
Once the mixture bubbles and liquefies take it off the heat and pour it all over the yams.
If using the air fryer cook for 10-15 minutes or until they are all warmed through. If using the oven cook for 30-40 minutes.
Once the yams are all warmed top them with the marshmallows. Up the temp on the air fryer to 400 and cook for 2-4 minutes. You are just cooking them until they are browned. If cooking in the oven cook another 10-15 minutes or just until the marshmallows are browned.