Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
Whisk the flours, baking powder, baking soda and salt together in a mix bowl then add in the sugar and salt and mix again.
In a separate bowl mix together the sour cream and whipping cream.
Add the grated frozen butter to the flour mixture and mix until the butter is incorporated. Add the cream and mix until you have a crumbly mixture.
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Tip onto a sheet of parchment paper and mold into a rectangle then roll out to approximately 12 x 10 inches (30 x 25 cm).
Tip the blueberries on top of the dough then using the parchment roll the dough up like a log then shape into a narrow rectangle 4 x 12” (10 x 30 cm).
Cut the strip into thirds then cut those diagonally so that you have six scones.
Please onto the baking tray and bake for around 20 minutes then remove from the oven and allow to cool completely.