Adapted from Joy the Baker.
The lotus paste is ideal here if it can hold its shape, almost like the consistency of fudge. If you have homemade lotus paste or your paste is very soft, cook it over low heat in a skillet to firm it up a bit.
If using buttermilk instead of Greek yogurt, use 6 tablespoons milk and ¾ cup buttermilk, adding the buttermilk where the Greek yogurt is called for.