In a medium bowl whisk together flour, baking powder, and salt. Cut butter into chunks and cut into flour using fingers or a pastry cutter until the size of small peas.
Add sugar and slowly mix in kefir until a dough forms. The dough should just hold together and not be too sticky. Knead briefly to bring the dough together and turn out onto a floured surface.
Roll out into a 1½-inch thick round or rectangle. Use a 2-inch biscuit cutter to cut out the scones and transfer to a baking sheet. Knead together scraps and cut into more scones until all of the dough is used up.
Bake 10-15 minutes. Transfer to a cooling rack and serve warm with cultured butter, clotted or whipped cream, and jam.