Add the diced russet potatoes to a pot of salted boiling water, reduce the heat and simmer the potatoes just until fork tender, about 5-7 minutes. Drain, rinse under cold water, and set aside.
In a large skillet, melt the butter over medium heat. Add the chopped onion and garlic, and sauté until the onion becomes translucent, about 5 minutes.
Add the diced corned beef and potatoes to the skillet. Spread them out in an even layer and let them cook without stirring for a few minutes to allow a golden crust to form.
Sprinkle the paprika and dried thyme over the mixture. Season with salt and pepper to taste.
Carefully flip the hash using a spatula to brown the other side. Again, allow it to cook without stirring for a few minutes.
Continue cooking and flipping the hash until it is heated through and has a nice crispy exterior, about 10-15 minutes in total.
Once the hash is ready, garnish with chopped fresh parsley if desired.
Serve the corned beef hash as a standalone dish or paired with poached or fried eggs for a classic and satisfying breakfast experience. Enjoy!