Wash and grate kaddu/lauki and put for boiling in a good amount of water. cover the lid partially, if the pot is covered completely it will boil and spill out. Stir a bit and when its color changes to transparent then it is cooked, press a small piece between finger tips to confirm. Drain out all the water and let it rest on the strainer for 5-10 min to cool down. meanwhile prepare the spices for it. Grind black pepper and cumin seeds in the grinder. always use freshly ground spices never use previously ground ones.
Add these ground spices, salt and yogurt in lauki and mix well It might look quite thick but as salt is added and lauki has moisture in it so it will become runny after a while so dont try to make it thin at this stage even if it looks very thick. Mix every thing well and tasted for the spices and adjust if needed. Serve in a bowl with black peppers sprinkled on the top. It is a good compliment with vegetable bhujias, and also with maash or channa daal.