Generally, for 1 cup of roasted vermicelli, I add 1 cup of water and then cook the vermicelli covered on low flame. However, since I have also used a cup of vegetables in this recipe, I have added another cup of water to the dish. Also, the amount of water slightly varies depending upon the quality of vermicelli. If you feel that the water has dried up but your vermicelli is not cooked properly, add some more boiling water to the pot and cook further.