1. Preheat oven to 400° F. Line two baking sheets with parchment paper for easy clean-up.

2. Toss the potato slices with the olive oil in a large bowl and generously season with salt and pepper; use your hands to ensure the potato slices are evenly coated. Spread them out on the baking sheets in a single layer and bake for 15 minutes. Flip the slices and rotate the pans, and bake an additional 10 minutes, or until potatoes are golden brown.

3. While the potatoes bake, melt the butter in a large skillet over medium heat. When the butter is hot and foaming, add the cabbage and ¼ teaspoon salt and sauté, stirring occasionally, until the cabbage is soft and just starting to brown, about 10 minutes. Set aside.

4. Cut the corned beef into ½-inch pieces (no need to separate into individual slices).

5. Once the potatoes are done baking, push the potatoes on one pan into the center of the pan, overlapping some slightly. Top with about half of the cabbage, corned beef (breaking it up a little as you do), and shredded cheese. Pile the potatoes from the second baking sheet over the first layer and then top with the remaining cabbage, corned beef, and cheese.

6. Turn the oven to broil and place the loaded potatoes back into the oven, a few inches away from the broiler. Broil for 2-4 minutes, or until cheese is melty and bubbly. Watch closely, to avoid burning.

7. Top with sauerkraut, green onions, and sour cream as desired and serve immediately.