Whisk Dry Ingredients: In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
Cut in Butter: Add cold butter cubes. Use a pastry cutter or fingertips to work the butter into the flour until it resembles coarse crumbs with some pea-sized chunks remaining.
Mix Wet Ingredients: In a separate jug, whisk sourdough discard, heavy cream, and vanilla until smooth.
Combine: Pour the wet mixture into the dry. Fold gently with a spatula. When halfway mixed, add chocolate chips. Continue folding until a shaggy dough forms.
Fold & Shape: Turn dough onto a floured surface. Pat into a rectangle and perform two "letter folds" to create layers. Shape into a 1-inch thick circle.
Cut & Chill: Cut into 8 wedges. Place on a parchment-lined tray. Chill in the fridge for 30 minutes.
Bake: Preheat oven to 400°F (200°C). Brush chilled scones with cream and sprinkle with coarse sugar. Bake for 18–22 minutes until deep golden brown.
Cool: Let rest on the tray for 5 minutes before transferring to a wire rack.