Preheat the oven to 400℉. Preheat a large cast iron skillet in the oven.
Cut the smaller potatoes in half and the larger ones in quarters. Add to the preheated skillet. Toss with 2 tablespoons of oil and salt and pepper.
Roast for 20 minutes, stirring after 10 minutes. The potatoes should be fork-tender and caramelized around the edges. Cool slightly and transfer the potatoes to a plate.
Heat the same skillet over medium heat. Add one tablespoon of oil and the diced peppers and onions.
Cook, stirring occasionally, for 8-10 minutes until the peppers and onions are softened and starting to caramelize.
Add the corned beef and cook for another 8-10 minutes until the corned beef is starting to caramelize.
Stir in the potatoes and cook for another 3-4 minutes until warm. Season to taste with salt and pepper, if necessary.
Notes
Potatoes: Leftover roasted potatoes are ideal for this dish. Skip the potato roasting steps and start by cooking the peppers and onions.Equipment: A cast-iron skillet helps to create the caramelized edges which adds so much flavor to the hash.Storage: Store leftovers in the refrigerator in an airtight container for 4-5 days.