Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt.
Add the cold, cubed butter to the flour mixture. Using a pastry cutter or your fingers, cut the butter into the flour until the mixture resembles coarse crumbs.
Gently fold in the diced peaches.
In a separate bowl, whisk together the heavy cream, egg, and vanilla extract. Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Turn the dough out onto a lightly floured surface. Gently knead the dough a few times to bring it together. Pat the dough into a round disk about 1 inch thick. Cut the disk into 8 equal wedges.
Place the scones on the prepared baking sheet, spacing them about 2 inches apart. Brush the tops of the scones with a little heavy cream. Bake in the preheated oven for 18-20 minutes, or until the scones are golden brown and a toothpick inserted into the center comes out clean.
Allow the scones to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
In a small bowl, whisk together the powdered sugar, 2 tablespoons of heavy cream, and vanilla extract until smooth. If the glaze is too thick, add an additional tablespoon of heavy cream. Drizzle the glaze over the cooled scones.