Preheat the oven to 190°C.
If you’re using raw sweet potatoes - peel and dice them (you'll need about 2 small ones), then cook them in boiling water for 5 minutes, until soft. Drain and mash them with potato masher. Let the mash cool.
In a bowl, mix the dry ingredients. In another bowl, mix the kefir, oil and mashed potatoes. Combine the two mixtures until you get a smooth dough.
Spoon dumplings onto a baking sheet, lined with baking paper, and press them down on the top into cookies.
Bake for 10 minutes until golden and risen.
Transfer them to a wire rack and let them cool before serving.