Place the sweet potato casserole in a microwave-safe dish.

Cover the dish loosely with a microwave-safe lid or plastic wrap. Make sure there's a small vent for steam to escape.

Microwave on medium power in intervals of 1 minute, stirring in between to ensure even reheating. Check the temperature and continue until it's heated to your liking.

Preheat your oven to 350°F (175°C).

Transfer the sweet potato casserole to an oven-safe dish if it's not already in one.

Cover the dish with aluminum foil to keep the moisture in.

Reheat for 20-30 minutes or until the casserole is heated through. The time might vary based on the size and density of your casserole.

Transfer the sweet potato casserole to a pot or large skillet.

Heat over medium-low heat.

Stir occasionally to ensure even heating and prevent the bottom from scorching.

Continue heating until the casserole is warmed throughout, which should take about 10-15 minutes, depending on the quantity.

Preheat your air fryer to 300°F (150°C).

Place the casserole in an air fryer-safe dish or spread it in a single layer to ensure even reheating.

Cook in the air fryer for 10-15 minutes, occasionally checking to ensure it doesn't dry out or overheat. If your casserole has a crunchy topping, be careful not to overcook as it can become too crispy or even burnt.