Combine all the dry ingredients together in a large bowl.
Grate butter into the flour mixture. Gently fold in the sour cream.
Carefully mix the dough together, being extra careful not to over-mix it. The dough should be crumbly in texture.
Roll the dough into a rectangular shape. Spread raspberries evenly over the dough. Fold over the dough, rolling it into a log shape. Cut the scones into similar-sized wedges.
Place scones onto a lined baking sheet, leaving space in between each other. Brush the tops with a whisked egg, followed by a sprinkling of sugar.
Bake at 350°F for 30-40 minutes or until scones are golden brown.