Peel the lauki using a peeler and grate it fine. In a microwave bowl, add grated lauki, little water and little salt.
Put it in to microwave for 5-6 minutes with lid on or until water gets evaporated completely and lauki gets soft. Once it done, let it cool down.
In a mixing bowl, add curd, milk, lauki, coriander leaves, black pepper powder, roasted cumin powder and salt. Mix all very nicely.
Lauki raita is ready. Refrigerate for about half an hour before serving and serve cool. Serve as a side dish with your meals. You can add chili powder if you want it to be spicy. Garnish with boondi and chili powder.