Begin by preheating your oven to 225 degrees F (110 degrees C). Prepare a baking sheet with a silicone liner and arrange the fresh raspberries on it, spacing them about 1 inch apart.

Bake the raspberries in the preheated oven for 4 hours. After this time, turn off the oven and leave the berries inside for an additional 8 hours or overnight.

When you're ready to make the scones, preheat the oven to 400 degrees F (200 degrees C) and line another baking sheet with a silicone liner.

Chop the dried raspberries into smaller pieces and measure out ½ cup for the recipe, setting aside any extra for later use.

Grate the white chocolate using the fine side of a grater until you have ½ cup.

In a mixing bowl, whisk together the flour, sugar, salt, and baking powder.

Grate the cold butter into the flour mixture, tossing it occasionally to prevent clumping. Once all the butter is added, use a pastry blender to work it into the flour.

Add the grated white chocolate to the mixture and toss with a fork to combine.

In a separate liquid measuring cup, whisk together the milk and sour cream, then pour this mixture into the flour blend. Use a fork to mix until the dough just comes together in a shaggy mass.

Transfer the dough to a generously floured surface. Without kneading, gently push and pack the dough together with your hands until it holds its shape, adding more flour if it feels too sticky.

Shape the dough into a rectangle about ¾-inch thick and roughly twice as long as it is wide. Evenly sprinkle the dried raspberries over the surface, pressing them gently into the dough.

Using a bench scraper, fold one third of the dough from one of the shorter edges over the center third, pressing it down and squaring off the edges. Repeat this with the other side, creating three layers of dough.

Cut the rectangle in half with the bench scraper, then slice each half into 2 triangles. Place the scones onto the prepared baking sheet.

In a small bowl, whisk together the egg and 1 tablespoon of milk. Brush this egg wash over each scone and sprinkle with sugar.

Bake the scones in the upper center of the preheated oven until they are golden brown, which should take about 25 minutes.

Once baked, carefully transfer the scones to a cooling rack and allow them to cool completely for about 30 minutes before serving.