Heat ham over medium low heat in large skillet until heated through and slightly browned.
Meanwhile, melt butter in medium skillet over medium high heat and add walnuts. Stir until walnuts are browning, about 2-3 minutes.
Add apple, maple syrup and brown sugar. Bring to boil and stir until sugar is dissolved and apple softens slightly, about 3 minutes.
Cut the ham slices in half, place ham slices on plates and ladle sauce over top. Serve immediately.
Notes
Apples: Any kind of apple will work with this recipe. Granny Smith apples (the green ones) have a more tart flavor, while Macintosh apples are sweeter. But any variety is great!
Nuts: You can swap in chopped pecans, slivered almonds or even peanuts for the walnuts. And if you need to leave them out altogether, that’s fine too.
Raisins: Want to up the flavor even further? Add a half cup of raisins when you add the apples.