Mash ki daal kay dahi baray or dahi bhallay taste best when made with just mash ki daal (white lentils). However, this particular lentil can be difficult to process into a paste, even after soaking. This can result in a coarse texture, and heating up of the machine. Having a good food processor or blender definitely helps. Or you can adjust the ratio of mash daal (white lentils) to moong daal (yellow lentils). This can be in a 1:1 ratio (½ cup mash daal and ½ cup moong daal), or in a 1:3 ratio (¼ cup moong daal and ¾ cup mash daal). My personal preference is the 1:3 ratio because that way you get the flavour and texture of mash ki daal, but you also get a little bit of the softness and ease of grinding from the moong daal.