Step 1: Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Step 2: In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, and salt until well combined.
Step 3: Add the cold, cubed butter to the flour mixture. Use a pastry cutter or two forks to cut the butter into the flour until it resembles coarse crumbs with some pea-sized bits remaining.
Step 4: In a small bowl, whisk together the mashed banana, heavy cream, and vanilla extract until smooth.
Step 5: Pour the wet ingredients into the dry ingredients and add the chocolate chips. Stir gently with a spatula just until the dough starts to come together.
Step 6: Turn the dough out onto a lightly floured surface. Gently knead it 2-3 times to bring it together, then pat it into a circle about 1 inch thick.
Step 7: Cut the circle into 8 equal wedges using a sharp knife or bench scraper. Place the wedges on the prepared baking sheet.
Step 8: Brush the tops of the scones with a little extra heavy cream and sprinkle with turbinado sugar if desired. Bake for 18-22 minutes, or until the edges are golden brown.
Step 9: Remove from the oven and let cool on the pan for 5 minutes before transferring to a wire rack. Serve warm.