While this can be done over stove top, I prefer a pressure cooker to cook my dal. Faster and hassle free. I add about 2 cups of water to cook my dal until soft. Takes around 10 minutes *as opposed to about 30 min on stove top.
Cool the cooked dal and then add it to a food processor. Retain the cooking liquid. You can add it while grinding and to adjust the consistency of your dip.
Add the rest of the ingredients and grind into a smooth puree. Add the reserved liquid as per your taste. Taste and season accordingly.