Preheat oven to 375, and line a large baking sheet with parchment paper.
In a medium bowl, whisk together the milk, half and half, granulated sugar, and 1 tsp salt until dissolved. Set aside.
In a large mixing bowl, combine the flour, baking powder, and 1 cup (two sticks) of the butter using a pastry cutter (or your hands). Continue to break up the butter until it is in mostly pea-sized bits.
Pour the milk mixture over the flour and combine until dough sticks together. Turn out onto a floured surface.
Roll the dough into a large rectangle, about 15" long and 8" high. Melt 2 tablespoons of butter and use a basting brush to spread it across the dough surface. Because the dough is cold, the butter should firm up a bit on the surface.
Fold the bottom half of the dough up to the middle, and then fold the top down over this- just like folding a letter to fit in a long, business size envelope. Fold the long rectangle in the middle to halve its length, and then fold it over again the same way.
Gently roll the dough flat again, until it is a rectangle about 8" high and 4" wide. Use a sharp knife to cut vertically down the middle, diving the dough in half. Cut each of the two columns into four pieces, making a total of eight scones.
Place the scones on the parchment paper and sprinkle liberally with demerara sugar, then lightly with the sea salt.
Bake 20-25 minutes, or until edges are golden.
While scones bake, clarify 4 tablespoons of butter on the stove. As soon as the scones come out of the oven, brush the tops with the butter and serve warm with topping of your choice.
