In a mixing bowl, whisk dry ingredients together. Sifting the flour, salt, baking powder, and sugar for a lighter texture. (optional)
Cut the cold butter into the dry mixture using a pastry cutter, fork, or your hands. If using my hands, I like to cube the butter first. Incorporate the butter until you get pea-sized crumbs.
Use a wooden spoon to stir the add-ins into the flour mixture — raisins, sliced almonds, and unsweetened coconut flakes. Or swap for your favorite add-ins.
In a separate small bowl, whisk together the wet ingredients — cream, sourdough starter, eggs, and vanilla extract. Active or discard will work.
Pour the wet ingredients into the dry, and then, using a wooden spoon or fork, mix the dough until it comes together (no worries, it will be fairly crumbly).
Dump the dough onto a lightly floured surface and use your hands to gently knead the dough into a disc shape. You can do one 10.5" disc cut into 8 wedges, or you can split the dough in two and shape two 8" discs for a total of 16 wedges. If you do one disc, the scones will be thicker and taller. My kids prefer the smaller size of the split batch. (Bake times will vary depending on how thick your discs are; see notes for details.)
Arrange wedges on a parchment lined baking sheet, brush the tops with cream or milk, and sprinkle with sugar. Bake scones in a preheated oven (375 degrees F) until golden brown around the edges. About 13-15 minutes if the dough was split in two, or 20-25 minutes if baking the thicker scones. Transfer baked scones to a cooling rack. Best served warm.