01 - Bring a pot of salted water to boil over high heat. Add diced potatoes and cook for 6-8 minutes until just tender when pierced with a fork. Drain thoroughly in a colander and set aside.
02 - Heat butter and vegetable oil in a large skillet over medium heat. Add chopped onions and bell peppers, sautéing for 3-4 minutes until softened and fragrant.
03 - Add cooked potatoes to the skillet. Cook for 5 minutes, stirring occasionally, until edges begin to develop golden color.
04 - Stir in diced corned beef and thyme. Press mixture into an even layer and cook undisturbed for 5-7 minutes until bottom is crispy and browned. Flip sections in batches and cook another 3-4 minutes for additional crispiness.
05 - Season hash generously with salt and pepper to taste. Remove from heat and keep warm while preparing eggs.
06 - Fill a saucepan with 2-3 inches of water. Add vinegar and bring to a gentle simmer over medium heat—water should have small bubbles but not be boiling vigorously.
07 - Crack each egg into a separate small bowl. Create a gentle whirlpool in the simmering water with a spoon, then carefully slide eggs in one at a time. Poach for 3-4 minutes until whites are fully set but yolks remain runny.
08 - Remove eggs using a slotted spoon and transfer to paper towels to drain excess water. Lightly season with salt.
09 - Divide crispy hash evenly among four plates. Top each portion with a poached egg. Garnish with fresh parsley and serve hot sauce alongside if desired. Serve immediately.