Steps
1. Preheat the oven to 350°F (175°C)
2. Place the slice of bread into the baking tray, then top it with the grated cheese, ketchup, mayonnaise and chopped onion.
3. Bake the quiche for 15 to 20 minutes, or until the cheese is melted and the bread is golden brown.
4. Serve and enjoy!