1. Preheat oven to 425 degrees.
2. Score and remove HALF of the wrapper from each stick of frozen butter. Holding the wrapped end, grate the unwrapped ends on the large holes of a box grater (you should grate a total of 8 tablespoons). Place the grated butter in the freezer until needed. Melt 2 tablespoons of the remaining ungrated butter and set aside. Save the remaining butter for another use.
3. Whisk the milk, sour cream and vanilla in small bowl; refrigerate until needed. Whisk the flour, 1/2 cup of the sugar, the baking powder, salt, baking soda and lemon zest together in a medium bowl. Add the frozen butter to the flour mixture and toss with your fingers until the butter is thoroughly coated.
4. Add the milk mixture to the flour mixture; fold with a rubber spatula until just combined. Transfer the dough to a liberally floured work surface. Dust the top of the dough with flour and with floured hands, knead the dough six to eight times, just until it holds together in a ragged ball, adding flour as needed to prevent sticking.
5. Roll the dough into a 12-inch square. Fold the dough into thirds, like a business letter, using a bench scraper or metal spatula to release the dough if it sticks to the work surface. Lift the short ends of the dough and fold into thirds again to form an approximate 4-inch square. Transfer the dough to a plate and chill in the freezer for 5 minutes. (*See illustration below)
6. Transfer the dough to a floured work surface and roll into a 12-inch square again. Sprinkle the raspberries evenly over the top and then gently press them down into the dough with your hands. Roll the dough, pressing to form a tight log. Lay the log seam side down and press it into a 12 by 4-inch rectangle. Using a sharp, floured knife, cut the rectangle crosswise into 4 equal rectangles. Cut each rectangle diagonally to form two triangles and transfer to a parchment lined baking sheet.
7. Brush the tops of the scones with the melted butter and sprinkle with the remaining 1 tablespoon sugar. Bake 20-25 mins or until the tops and bottoms are golden brown. Allow to cool slightly and then drizzle with the glaze

To make the glaze

1. Combine all the ingredients and mix until smooth. Drizzle on top of warm scones.