Preheat oven to 375°F and cover a baking sheet with a non-stick silicone baking mat or parchment paper. Prepare a workspace by creating a lightly-floured surface.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.
Cut butter into pieces (about 1/2 inch thick) and then add them to the dry ingredients. Use a pastry cutter to cut in butter until the mixture looks shaggy and the butter pieces are about the size of peas.
Add the vanilla and gradually pour the milk into the mixture, stirring with a spatula as you do. Once all milk is added, switch to using your hands. As you work the dough, gradually add in the frozen raspberries. Gently knead the dough until raspberries are spread throughout and it all holds together in one mound.
Transfer the dough to the lightly-floured surface. Using your hands, shape the dough into a round shape. Gently flatten the dough into a disk that is about 1 - 2 inches thick.
Use a sharp knife to cut the disk into 6 even wedges.
Transfer the wedges to the prepared baking sheet and bake for 20-30 minutes, or until the scones are golden-brown, puffy, and baked through.
