• Preheat oven to 400F/205C.
• Cover cranberries with warm water and soak for 10 minutes, then drain well.
• In the bowl of a food processor, place the flours, milk powder, baking powder, baking soda, salt, sugar, and lemon zest. Pulse a few times to combine.
• Cut the cold butter into 1/2 inch cubes and add to the processor. Pulse several times until mixture resembles coarse cornmeal with a few larger (pea-sized) pieces of butter remaining.
• Transfer the mixture to a bowl and mix in the oats and drained cranberries lightly with your fingers.
• Add the sourdough starter and mix quickly and lightly just until the dry ingredients are incorporated. The dough will be wet and sticky. Do not attempt to make a smooth dough, no kneading needed! Lightness is a virtue! Mixing the dough briefly will avoid developing the gluten which toughens the scone. If the dough is too sticky, wait a minute or two.
• Turn the dough out onto a well-floured counter and pat into a rectangle about 5x9 inches or a round shape about 7x7 inches, 1 inch thick.
• With a dough cutter, divide the dough into wedges.
• Place scones on ungreased or parchment-lined baking sheet. Brush with milk and sprinkle with coarse sugar. Bake for about 23 minutes until golden brown. Serve warm.

Instructions for Freezing

• If you want to freeze the scones for later, do not bake --- place cut scones uncovered on parchment paper on flat sheet and put in freezer. Leave until quite frozen about 2 hours. Remove and put in freezer bag or container, label with baking time and temperature, and save for up to three months time.
• When desired take out however many frozen scones you need, place on ungreased or parchment paper-lined baking sheet. Brush with milk and optional sugar. Placing the scones closer together will bake into softer sides, otherwise about 1 inch apart will create crusty sides. Preheat the oven to 400F/205C.
• When oven is ready, bake for about 25-28 minutes, watch carefully. do not overbake. Serve warm.