Grease the insert of a 6-quart slow cooker with non-stick cooking spray or a bit of oil.

Slice the potatoes VERY thinly and uniformly. *A mandolin slicer works great for this!

In a medium saucepan or skillet over medium heat, melt the butter; add the diced onions and garlic and cook until translucent. Sprinkle the flour over the top and continue to cook, stirring often, until the mixture is golden brown, 1-2 minutes.

Remove the pan from the heat; use a flat whisk to gradually whisk in the chicken broth and heavy cream until smooth. Stir in the dried oregano, paprika, salt, and pepper.

Return the pan to medium heat and continue cooking, whisking constantly, until the sauce thickens, 3-4 minutes.

Layer one third of the sliced potatoes over the bottom of the greased slow cooker insert.

Pour one-third of the prepared sauce over the potatoes followed by a third of the cheddar cheese and a third of the diced ham. Repeat the layers two more times.

Cover the slow cooker and cook on low heat for 4-5 hours, or until the potatoes are tender when tested with a fork and the sauce is bubbly, creamy, and thickend. **It is not recommended that the scalloped potatoes be cooked on high since this can cause the cream sauce to curdle and to also scorch on the bottom and the sides.

Once cooked, garnish the potatoes with chopped fresh scallions, as desired. Serve at once. **Scalloped potatoes will continue to thicken as they cool.