In a mixing bowl, add 2 cups murmura (puffed rice) and wash it well. Then add 1 cup rava (semolina), 1 cup sour curd, and 1 cup water. Mix well.
Cover and rest for 15–20 minutes so the rava puffs up and the murmura soaks properly.
After resting, transfer the mixture into a blender jar and grind it to a smooth batter.
Pour the batter back into the mixing bowl and whisk it for 2–3 minutes.
Check the consistency — if the batter is too thick, add a little water. The batter should be medium-thick and of pouring consistency.
Add ½ tsp baking soda and 1 tsp lemon juice. Mix well.
Heat a tawa, sprinkle some water, wipe it with a cloth, and bring the tawa to the right temperature.
Pour 2 small ladles of batter onto the tawa and spread it evenly.
When the top surface of the dosa begins to dry, drizzle some oil around the edges.
Cook on medium flame until golden brown. Fold and serve hot with chutney or sambar.