1. Spread a generous layer of mint mayo on a slice of bread.
2. Layer with sliced cucumber and onion
3. Sprinkle some salt and pepper
4. Top it with another slice of bread and spread a generous layer of mint mayo on this as well.
5. Layer this with slices of  tomato and green capsicum.
6. Top this with grated cheese and third slice of bread
7. Grease both ends of the sandwich with butter and grill.
8. Serve hot.

Enjoy your meal!