Finely chopped tomatoes.
In a pan, add oil. Add mustard seeds and let it splutter.
Now add chopped tomatoes and cook it till soften up.
Once it get Cooked, add turmeric, red chilli powder, dhaniya powder and salt.
Now add water and let it boil.
After water starts boiling, add salt to taste of sev. Mix well and add sev.
Cook it for two minutes and it's done.
Serve this spicy sev Tamatar subji with roti