Preheat oven to 375F and line a baking sheet with parchment paper or a silicon mat. Whisk flour, baking soda, baking powder, salt and sugar together in a large bowl. Add in butter, toss to coat, and rub in with your fingers (or a pastry cutter, if you prefer) until only pea-sized chunks remain. Stir in cranberries and chocolate chips(or other mix-ins), then add the cream and buttermilk, mixing only until the ingredients just come together into a ball. It is ok if there is a little flour left at the bottom of the bowl. Divide dough into 12 balls (about 2-in in diameter) Sprinkle the top of each with coarse sugar and a tiny pinch of kosher salt before placing on the prepared baking sheet. Bake for 25 to 30 minutes, until golden brown. Cool on a wire rack. Other mix-ins: 1 cup dried blueberries Orange zest and chocolate candied lemon peel and lemon zest