1. Preheat the oven to 400 degrees F. Line a baking sheet with parchment or a silicone mat.
2. Whisk the flour, sugar, baking powder, and salt together in a large bowl. Drop in the butter and, using your fingers, toss to coat the pieces of butter with flour. Use your fingers or a pastry blender, cut and rub the butter into the dry ingredients. You will have some small pea size pieces of butter and that is fine. Gently stir in the blueberries and strawberries.
3. In a small glass measuring cup or bowl, whisk together the egg, heavy cream, and vanilla extract. Pour mixture over the dry ingredients and stir with a spatula just until the dough comes together. Carefully knead the dough by hand, just until the dough comes together.
4. Lightly dust a work surface with flour and turn out the dough. Pat the dough into a circle. Gently roll out the dough. You want the dough to be about an inch thick. Cut the dough into star shapes using a cookie cutter. Place the scones on the prepared baking sheet, about 2 inches apart. Lightly brush the scones with cream and sprinkle with turbinado sugar.
5. Bake for 12-14 minutes, or until golden brown. Transfer shortcakes to a rack and cool to cool to room temperature. Once cooled, drizzle each scone with white chocolate. Let stand until chocolate is dry.