Heat oven to 200°C upper/lower heat. Line baking tray with baking paper.
Whisk together eggs, buttermilk and lemon peel. Lightly mix flour, Hermesetas Granulated, baking powder, baking soda and salt. Quickly mix the butter into the flour mixture with your fingertips until only pea-sized pieces remain. Add the egg-buttermilk mixture and stir briefly with a cooking spoon until everything is blended ever so slightly. The dough should not be processed for too long so that the butter remains cold and the scones turn out light and flaky.
Carefully mix in the blueberries. Place the dough on a floured countertop and form it into a disc roughly 2 cm thick and 20 cm in diameter. The dough is a bit difficult to process, but that is normal. Cut the dough disc in 8 equal size pizza slices. Mix the egg yolk with milk and coat the scones with the mixture.
Bake for approximately 20 minutes in the heated oven until the scones are light-brown. Remove them from the oven and let them cool for 10 minutes on a cake rack. Serve lukewarm.