In a large skillet, heat butter over medium heat. Add onions, peppers and garlic. Sauté until onions are softened (about 3-5 minutes).
Add potatoes and corned beef. Continue sautéing until potatoes are heated through (about 10 minutes).
Add thyme and rosemary. Salt and pepper to taste. Continue sautéing 5 minutes.
Serve with poached eggs, if desired.