Keep the butter in the fridge till the minute you need to use it.

Mix flour, baking powder, baking soda, and salt.

Combine milk and sour cream and set aside.

Sift some of the dry flour mixtures on a workbench, grate cold butter over it, and sift the rest of the flour mixture over the grated butter.

Add sugar and zest to it. Toss and rub this mound with a pastry cutter to combine everything. Don't overwork it as it will melt the butter pieces.

Pour the milk and sour cream mixture over the flour, sugar, and butter mixture. Mix everything with the back of a fork or a pastry cutter. Work the dough gently till it comes just together. Don't knead it too much as we are not looking for a smooth textured dough.

Spread the dough into a square and fold in thirds like a letter. Fold it again in thirds. Transfer it to a plate and refrigerate for 30 minutes.

Take it out and spread the dough again into a square. Spread the blueberries all over the surface of the dough and press on them gently so they can embed in the dough. Roll it into a log like I did in the video. Pat on the log and make it 12 inches long. Then cut into four equal portions. Cut the four parts again into triangles. You should have a total of eight scones.

Transfer scones to a greased baking tray. Top them with chunks of butter and sprinkle some sugar on. Bake in a preheated 425F oven for 20 minutes.

Cool for 5 minutes in the tray and then transfer them to the wire rack to cool completely.

Glaze them if you want them to be sweeter.