Heat a small pressure cooker, and then add ghee.
Add jeera, and when jeera splutters, add hing and haldi. (I know a lot of women add haldi after adding sabzi instead of adding it in the tadka. They say it's to prevent the haldi from getting burnt. But I'm used to making the tadka this way. I do add the sabzi immediately after adding haldi though.)
Add chopped lauki and stir it properly. Since I used pre-cooked vegetables I didn't add them at this stage but if you want to use freshly chopped vegetables, add them along with lauki. In my mixture of mashed vegetables I had tomato, carrot, cabbage, cauliflower, red pumpkin, and lauki again. :-)
Add half to three-fourth cup water, depending on the desired consistency of the sabzi. (Add more water if you want to serve this sabzi with rice.)
Cover the pressure cooker with its lid and cook on medium-low heat for about 8-10 minutes (3-4 whistles).
Take off the lid after 3-4 whistles, and then add mashed vegetables and mix them properly with the cooked lauki.
Add salt and garam masala powder, and cook for a couple of minutes. (Now I must confess I used readymade garam masala powder. I didn't use readymade ingredients in Devansh's food until recently. But I'm being a tad bit easy going about readymade stuff now that he's 2.5 years old. But it's best to use homemade masala, especially if you're cooking for younger kids.)
Add chopped coriander and cook for a minute more. (Coriander is better eaten raw than cooked but most toddlers find it difficult to chew coriander. So it's better to cook it a bit to make it slightly soggy.)
Serve hot with chapatis or rice.