A large skillet or sautée pan on at medium high. Eyeball a couple of tablespoons of olive oil. Put your leftover potatoes - or yams - in the pan. The only leftovers we had was ham but Judy makes great baked beans in big batches and we always have some in the freezer.
If you also have some other veggie left over put them in too. We didn't, but baby carrots are a regular in the fridge so,, in they went. Any quick cooking veggie like broccoli or peas would also work.
Get it up to a simmer and lay the ham slices on top. Sprinkle a little brown sugar on top - if you want to. I couldn't resist the urge.
Mix it together and let it cook until the ham has heated up and the veggies are done.
Then serve up your super good, super quick, super easy treatment of your leftover Christmas ham.
Notes
Obviously whatever leftover meat will work i.e. leg of lamb, roast pork, roast beef, turkey etc.