01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together the flour, sugar, baking powder, and salt until well combined.
03 - Add the cold butter cubes. Using a pastry cutter or your fingertips, work the butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized pieces remaining.
04 - In a separate bowl, whisk together the heavy cream, sour cream, egg, and vanilla extract until smooth.
05 - Pour the wet mixture into the dry ingredients. Stir gently with a spatula just until the flour is moistened and a shaggy dough forms.
06 - Gently fold in the diced strawberries using light strokes, taking care not to overmix or crush the fruit.
07 - Turn the dough onto a lightly floured surface. Pat gently with your hands to form a 1-inch-thick round disc.
08 - Use a sharp knife or bench scraper to cut the dough into 8 equal wedges. Transfer to the prepared baking sheet, spacing 2 inches apart.
09 - Brush the tops of each scone with heavy cream and sprinkle with coarse sugar if using.
10 - Bake for 16 to 18 minutes until the tops are golden brown and a toothpick inserted into the center comes out clean.
11 - Let scones cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before serving.