To prepare Udupi Hotel style tomato omelette, in a large bowl, mix together flours, turmeric powder, red chilli powder and salt. Add 3/4 cup water to this. Mix well. Cover and keep aside for 10 minutes.
Meanwhile chop the vegetables. Halve the tomatoes and slice thinly. Peel, halve and thinly slice the onions. Chop the coriander leaves finely. Slice the green chili finely.
Add all the chopped ingredients to the batter.
Add a pinch of baking soda to the batter and squeeze the lemon over it. The soda will bubble up. Using a spoon, mix it well into the batter. This should have a pouring consistency but not very thin.
Grease a non-stick tava with 1/2 tsp oil and place on medium flame.
Pour 2 small ladles of batter. Spread out the vegetables evenly through the ‘omelette’ using a spoon, but don’t spread out the batter thinly. The thickness should be roughly 1/2 cm or more.
Trickle a teaspoon of oil around the edges and allow this to cook for 3-4 minutes on one side on a medium flame. Once you see bubbles around the edges, you can flip it over. Add a little oil around the edges once again and cook for 3-4 minutes.
Prepare tomato omelettes with the remaining batter.
Serve warm with tomato ketchup or green chutney or as an ‘omelette’ sandwich between two slices of buttered bread.