corned beef hash recipe

### Ingredients: - **2 cups** cooked corned beef, diced - **3 cups** cooked potatoes, diced - **1/2 cup** onion, finely chopped - **2 tablespoons** unsalted butter - **2 tablespoons** olive oil - **Salt and pepper**, to taste - **2 tablespoons** chopped fresh parsley (optional) - **4 large eggs** (optional, for serving)