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