In a large bowl, whisk flour, sugar, salt, cardamom and baking powder together. Grate the frozen butter using a box grater. Once it's finished, add it to the flour mixture and combine with your fingers until the mixture comes together in pea-sized or smaller crumbles. Place in the refrigerator or freezer to re-chill the butter mix as you mix the wet ingredients together.
Whisk 1/2 cup almond milk, egg, and vanilla extract together in a small bowl. Drizzle over the flour mixture, add the add-ins (blueberries) then mix together until everything appears evenly moistened.
Pour the dough mix onto a lightly floured counter or on a cutting board (this is my preference, in case you need to re-chill the dough) and, with floured hands, work dough into a ball as best you can. Dough will be sticky! If it’s too sticky, add a little more flour, about a tsp sprinkled over the mix at a time. If it seems too dry, add 1 tsp almond milk.
Press into an 8-inch disc and, with a sharp knife cut into 8 wedges. If dough starts to get too warm, you can place the disc into the freezer for a few minutes to re-chill before slicing. For smaller scones, press dough into two 5-inch discs and cut each into 8 wedges.
Brush the scones with remaining almond milk and sprinkle with some granulated sugar, or for extra crunch use raw course sugar.
Place scones on a plate or lined baking sheet or cutting board and refrigerate for at least 15 minutes before baking. While they are chilling, set the oven to 400º F
Line a large baking sheet with parchment paper. Set the scones about 1.5 inches apart from one another. Bake for about 20 - 22 minutes and keep a close eye on them. Once the tops start to brown a little they should be finished. Let them cool on a cooling rack and add icing, butter, or another sprinkle of sugar and enjoy!