Steam the chopped sweet potatoes until they are tender, but not mushy. Alternatively, cube and roast them until tender. Do not let them get mushy.
Allow the sweet potatoes to cool slightly in a bowl, and then add the scallions and parsley.
Mix the ricotta with salt and pepper to taste and set aside.
Put all the dressing ingredients together and shake or whisk until combined. Pour the dressing over the sweet potato mixed and toss gently to combine.
Drop spoonfuls of the ricotta all over the top and serve.
Adapted from The Moosewood Restaurant Cookbook