1. Take a tissue paper and press it over the chopped tomatoes. Ensure that all the liquid from the tomatoes is absorbed. 
2. In a mixing bowl add tomato, onion, basil leaves, olive oil, pepper powder and salt. 
3. Refrigerate the onion and tomato mixture for 20 minutes. 
4. Slice the bread diagonally into 1/2 inch thick slices. Apply butter on both sides of bread slices. 
5. For this, heat a tava and toast the slices till they turn brownish. 
6. Once the slices cool, arrange them on a plate. 
7. Top the toasted slices with 1-2 tablespoon mint mayo. 
8. Top this with 2 tablespoon of onion tomato mixture and serve. 

Enjoy your meal!