In a small grinder take 1 teaspoon chopped ginger, 1 teaspoon chopped garlic, 2 teaspoons chopped green chilies.
Add 1 tablespoon water and grind to a smooth paste. Keep aside. You can even crush ginger, garlic and green chilies in a mortar-pestle.
Rinse, peel and grate 1 small bottle gourd (lauki, ghia, dudhi, opo squash). You will need 1 cup tightly packed grated bottle gourd.
Heat 1 tablespoon oil in a small pan.
Add ½ teaspoon mustard seeds and let them crackle.
Then add 5 to 6 fenugreek seeds, 1 pinch asafoetida and 1 teaspoon chopped curry leaves.
Fry for a few seconds.
Then add the ginger+garlic+green chilli paste.
Saute till the raw aroma of ginger and garlic goes away.
Add 1 cup tightly packed grated bottle gourd.
Also add ½ teaspoon turmeric powder and ½ teaspoon coriander powder.
Mix well and then switch off the flame.
Now add ¼ cup chopped coriander leaves and mix well again.
Add the tempered bottle gourd mixture to the handvo batter.
Add salt as required and again mix very well.