Starting this hash with leftover, cooked potatoes is not just a time or money saving technique. Using the cooked potatoes makes the best hash browns, ever!
Cook potatoes in boiling salted water to cover until just tender, about 3 minutes, then drain, cool and dry, or even better, use leftover potatoes and dice.
Heat a large skillet, or two smaller skillets and add the oil. If you’re using a smaller skillet, you’ll need a bit more oil. The biggest mistake, in my opinion, is to not use enough oil and then have to add more, then a bit more. The second is to overcrowd the pan. To get a beautiful crunch with a creamy center to the potato, use this shallow fry method. Excess oil will be drained off.
When potatoes are nearly done, add the corned beef. Stir around as the corned beef darkens and crisps. Add green onion. Tilt pan and allow to drain, spoon off extra oil. Salt and pepper to taste.
Place Hash on plate or serving platter, top with a poached egg.
Alternatively, after the excess oil is drained, make several holes in the hash and drop an egg into each. Turn heat to a moderate setting, cover and cook to desired doneness.