Add in Tomato, Onion and tomato into a blender and blend them into a smooth paste.
Soak rice, Tur dal and urad dal in sufficient water for atleast 2 hours along with cumin seeds and dry red chillis. After 2 hours drain the excess water and grind the dals in a wet grinder or in a Mixer with only required water.
Add the tomato paste into the rice paste. Leave it aside for 3 hours.
After 3 hours take the batter and mux well with a ladle. The batter is now ready to make dosas. Adjust the water consistency if it is very thick.
Heat the dosa tawa and pour the dosa batter over the tawa.
Flip sides of the dosa until crisp. I love to serve it crisp.
yummy tomato dosa is now ready to serve with delicious coconut chutney.
Notes
If the batter is left for 3 hours it would ferment and taste better.