How do yall reheat your casseroles? I’m cooking for one, but I make large meals that can provide 4+ servings for me.

Recently I made a few different casseroles, I’ve found out that I can’t just put these servings in the microwave for a few minutes. I always have to cut it up, but I’m still having trouble gauging how long to cook it for.

What do you do with thick casseroles?