Heat the butter in a nonstick pan over medium low heat. Saute the onion, pepper, and corned beef until the onions and peppers are soft. Season with salt and pepper to taste.
Heat oil in a non-stick pan over medium heat. Once the pan is hot, crack the eggs on a flat surface and into the pan (being careful not to break the yolks). Cook the eggs until the whites are mostly firm for about 2-3 minutes, then gently flip the eggs with a spatula and cook for 30 seconds more. While the eggs are cooking, toast the bread.
Serve the eggs and corned beef with toast and grapes.