Preheat the oven to 425° (210°C) and line a baking sheet with parchment.
In a bowl, whisk flour, sugar, baking powder baking soda, and salt.
In another bowl, whisk heavy cream, milk, and vanilla.
Using a pastry blender or your fingers, cut butter into the flour mixture until the mixture resembles coarse breadcrumbs. A few larger bits of butter are perfectly fine.
Pour the wet ingredients into the flour and butter mixture and quickly stir until it starts to come together.
Turn dough onto a floured surface and knead just a few times until a dough is formed. It’s okay to see bits of butter through the dough.
Roll the dough into a 12x16 inch rectangle and sprinkle raspberries onto the surface.
Roll the dough into a tight log and then with the rolling pin reroll into a 1-inch thick rectangle.
Cut dough into 8 large triangles and place them on the baking sheet.
Place the pan in the fridge for 15 minutes to firm up the scones.
Remove scones from the fridge, brush the tops with the beaten egg and sprinkle with coarse sugar.
Bake for 25-30 minutes, until the tops are golden and they sound slightly hollow when tapped.
Let cool for 10 minutes on the baking sheet before enjoying.
Store any leftover scones in an airtight container at room temperature for up to 3 days, or freeze for up to 2 months. Defrost in a 300°F/150°C oven.