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, cut 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 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 dough begins to come together. Do not overmix.
06 - Gently fold in the diced strawberries, being careful not to crush them or overwork the dough.
07 - Turn the dough onto a lightly floured surface. Pat it gently into a 1-inch-thick round disc.
08 - Use a sharp knife or bench scraper to cut the dough into 8 equal wedges.
09 - Transfer the scones to the prepared baking sheet, spacing them about 2 inches apart.
10 - Brush the tops of each scone with heavy cream and sprinkle with coarse sugar if desired.
11 - Bake for 16 to 18 minutes, or until the scones are golden brown on top and a toothpick inserted in the center comes out clean.
12 - Cool on the baking sheet for 5 minutes, then transfer to a wire rack for an additional 5 to 10 minutes before serving warm.