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.

Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.

In a separate small bowl, whisk together the egg, heavy cream, and vanilla extract. Pour this wet mixture into the dry ingredients and gently stir until just combined. Do not overmix.

Gently fold in the diced nectarines until evenly distributed throughout the dough.

Turn the dough out onto a lightly floured surface. Knead gently 2-3 times, then pat or roll the dough into a 3/4-inch thick circle or square. Cut into 8 equal wedges.

Place the wedges on the prepared baking sheet, about 1 inch apart. Bake for 13-15 minutes, or until the tops are lightly golden brown and a toothpick inserted in the center comes out clean.

While the scones cool slightly, prepare the glaze: whisk the powdered sugar and milk until smooth. Drizzle over the warm scones before serving.