Position an oven rack in the lower third of the oven. Preheat to 205 degrees C and line a baking tray with baking paper.
Put flour, sugar, baking powder and salt in a large bowl and mix well.
Cut in the butter with a pastry blender or two table knives until the largest pieces of butter are about the size of peas. Set aside.
In a small bowl, stir the cream and egg yolks just to blend and then add to flour mixture. Stir with a fork to begin combining the wet and dry ingredients and then use your hands to gently knead the mixture together. All the dry ingredients should be absorbed into the dough so that you can create a moist ball. Don’t over-knead - the ball will be sticky but the scones will not be as light and flaky is dough is over-handled.
Set the ball in the centre of the baking sheet, patting and forming it gently into a disc about 2 1/2 cm thick and 18cm in diameter.
With a sharp knife cut the disc into eight wedges and separate.
Take each wedge and cut in half horizontally, leaving one of the corners connected so scone doesn't completely come apart. Place berries in between layers, putting top layer back and gently pushing back together without squishing down the scone.
Brush the scones with some melted butter and sprinkle with demerara sugar or some other large-crystal sugar that doesn't melt.
Bake until the scones are deep golden and a toothpick inserted into the centre of a wedge comes out clean, 18 to 22 minutes. Slide the baking paper onto a rack and let the scones cool for 10 to 15 minutes before serving.
Of course fresh berries are preferable to frozen, but both work well. You can also replace scones with dried fruit like currants, cranberries or cherries.