Puree 2 tomatoes in a blender and finely chop 1 tomato and keep aside.
In a bowl, add chickpea flour (besan) and rice flour.
To this, add finely chopped onions, ginger, green chilies, finely chopped coriander leaves, Kashmiri red chili powder, turmeric powder and Hing or asafoetida.
Next, add tomato puree and finely chopped tomatoes. Mix well.
Add some water and whisk to a batter consistency. Add salt to taste.
Heat a flat tava or griddle, add few drops of oil and season the pan. Note - This step prevents the omelette from sticking or tearing.
Carefully pour a ladle of tomato omelette batter and spread in a circular motion. Drizzle oil in the center and side and let it cook until the edges are crisp and brown.
Using a spatula, lift the omelette, turn and cook on the other side. Repeat the process with the rest of the batter. Serve tomato omelette hot with a side of your choice.