Scones can be heavy and dry, but happily that's not the case here. The key to success lies in minimal mixing and handling to keep the scones from becoming tough.These scones aren't particularly sweet, relying on the natural sweetness of the raisins rather than a lot of sugar in the batter. Try adding a handful of dried cherries or cranberries to augment the raisins, or 1/4 cup of minced crystallized ginger for a bit of spiciness.You can bake the scones in a round cake pan and cut them into wedges, or form 8 individual scones and cook them on a baking sheet.
Position a rack in the middle of the oven and preheat to 425 degrees F. Heavily butter a 9-inch round baking pan or a rimmed baking sheet.
Place the egg, vanilla, 1/2 cup of the buttermilk, sugar, and lemon rind in a medium-size bowl and whisk to combine.
In another large bowl, combine the flour, baking soda, baking powder, salt, and nutmeg, and whisk to blend.
Cut the butter into 16 small cubes. Add the pieces to the flour mixture and blend with your fingers into the mixture resembles coarse meal. Add the buttermilk mixture and raisins, and stir with a fork until the dough is just mixed.
Transfer the dough to the prepared cake pan and brush the top with the remaining buttermilk. Sprinkle the remaining 2 tablespoons of sugar over the dough. Alternately, turn the scone batter out of the bowl and gently pat it into a 3/4-inch-thick circle. Cut into 8 wedges and transfer these to a buttered baking sheet, spacing the scones three inches apart. Brush with the buttermilk and sprinkle with sugar.
Bake until the scones are golden brown and a toothpick inserted into the middle comes out clean, 15 to 25 minutes. If you bake the scones individually, they will cook more quickly.
Let the scones cool in the pan for 5 minutes, then turn out onto a wire rack to finish cooling.