Preheat the oven to 425 degrees F and line a rimmed baking sheet with parchment paper.

Whisk together the flour, sugar, baking powder, soda, and salt. Cut the cubed butter into the dry ingredients with a fork, pastry cutter, fingers, or two knives. (Or use a food processor with the metal blade to speed things up. Just a couple of pulses will do.)

Fold the frozen raspberries into the dry mixture and coat. Make a well in the center and pour in ¾ cup of buttermilk. It's better to add too little and add more as necessary. Work with the ingredients until it begins to form a dough. You may need to increase the buttermilk. Most often I need a bit more than ¾ cup and up to about 1 cup.

Transfer the dough to a floured surface and divide it into 2 parts. Roll each part into a round shape about 1 inch thick. Cut each disc into 6 wedges and place slightly separated on the prepared baking sheet. Brush with additional buttermilk or milk and sprinkle with sanding sugar if desired.

Bake for 14-18 minutes, or until the top begins to turn golden brown.

For the glaze: combine the lemon juice, confectioners' sugar and melted butter in a small bowl. Whisk until the lumps disappear. Once the scones have cooled, drizzle each scone with glaze.