Mix all the dry ingredients- flour, sugar, baking powder and salt. Now, mix the wet ingredients. Mix both wet and dry ingredients in a bowl and make a smooth, non-lumpy batter.
Heat a dosa tawa or frying pan over medium high heat. Pour some oil on it. Now, pour the batter for one medium sized crepe, like for a dosa. Make sure the batter spreads over the pan evenly.
Cook the crepe till the bottom 'sizzles' and changes colour to dark brown. Flip and cook the other side. Make all the crepes this way.
Cook filling: Heat a pan over medium heat. Add oil. Add jeera. After 30 seconds, add ginger, then add haldi and salt. When jeera pops, add potatoes. Add onions. Cook uncovered till potatoes start changing colour to a rich brown. Add spinach and green chillies. Stir till spinach changes colour and wilts. Stuff this mixture into the crepe. Serve!
For Non Veg: Chop a variety of meats and add grated cheeses into hot crepe. For a Paneer-veggie variation, use: 1 tsp oil. 1 medium tomato, chopped. 25 gm paneer, finely grated. Salt to taste. Sprig of mint or coriander, chopped. In a wide pan, lightly cook ingredients in the order mentioned. Stuff into crepe. Serve hot with ketchup.