Heat a pan with oil and add mustard followed by cumin seeds. Let them splutter and add curry leaves and asafoetida. Add finely chopped green chili and onion.
Fry until onion turns soft. Add finely chopped tomato . Add required salt.
Add red chili powder, cumin seeds powder, garam masala powder, turmeric and coriander leaves.
Add carrots. Continue cooking for another two mins until the spices blend in well. At this point add the nutmeg powder, ketchup and sugar [if using]
To serve, heat a pan and toast bread slice with butter. Toast bread until crisp and golden on both sides in medium flame. Press gently with spatula for even browning.
Spread 2 tbsp of the prepared masala in top of the bread slice and Let it stick well.