Preheat oven to 325°F convection or 350°F conventional. Line a baking sheet with parchment.

In the bowl of a stand mixer fitted with the paddle attachment, combine flour, sugar, salt, and baking powder. Mix on low just to distribute. Add cold cubed butter and mix on low until no visible butter remains and the mixture resembles wet sand.

Whisk together vanilla, eggs, and heavy cream in a separate bowl until smooth. With the mixer running on low, slowly pour in the cream mixture and mix until just incorporated.

Turn the dough out onto a clean surface. Add white chocolate chips and squeeze the dough together gently until no dry spots remain. Add frozen raspberries and fold them in gently, squeezing to break apart any clumps as you go.

For uniform scones, roll or press dough into a 6-inch square, roughly ½ inch thick. Divide into four 3-inch squares, then cut each diagonally to form 8 triangles. For rustic scones, press into a circle and cut into 12 triangles. Place on the prepared baking sheet about 2 inches apart.

Brush scones immediately with heavy cream and sprinkle generously with white sparkling sugar. Bake right away, do not refrigerate before baking.

Bake 18 to 20 minutes, until edges look dry and set and the centers offer light resistance when pressed gently with a fingertip. If baking from frozen, bake 20 to 25 minutes at the same temperatures.

Cool completely on the baking sheet.