01 - Heat 1 tablespoon oil in a large skillet over medium-high heat. Add diced potatoes and season with salt, pepper, and garlic powder. Cook, stirring frequently, until golden and crisp, approximately 12–15 minutes. Remove from skillet and set aside.
02 - In a mixing bowl, combine shredded cabbage, grated carrot, green onions, parsley, mayonnaise, Dijon mustard, apple cider vinegar, salt, and pepper. Toss thoroughly until all ingredients are evenly coated. Set aside to allow flavors to meld.
03 - Add remaining oil to the skillet and place over medium heat. Add shredded corned beef and sauté for 2–3 minutes until heated through, stirring occasionally.
04 - Warm tortillas in a dry skillet over medium heat for 30 seconds per side or microwave in batches of 2 for 20 seconds until soft and pliable.
05 - Layer each tortilla with crispy potatoes as the base, top with warmed corned beef, and add a generous spoonful of cabbage slaw. Drizzle sour cream over the top.
06 - Arrange tacos on serving plates and serve immediately while tortillas are warm and potatoes remain crisp. Offer additional slaw on the side if desired.