Boil, carrot, peas and cauliflower in 2 cups of water. Drain and cool.
In same pan boil another 4 cups of water add vermicelli, salt and few drops of oil. Cook till slightly underdone. Drain and keep it aside.
Heat oil in a wok add mustard seeds, curry leaves and urad daal. Let it splutter. Now add ginger and onion, fry them until onion becomes little brown.
Add green chilies and semi cooked vegetables and saute for few minutes. Then add cooked vermicelli, stir gently for 6 -8 minutes. Switch off the flame. Sprinkle lemon juice and serve hot