Sift together all dry ingredients, except for baking soda.
Cut in the butter. Go through with fingers, making sure the butter is in pieces no larger than grains of rice.
Toss in the raisins.
Stir together the milk and egg and mix it into the dry ingredients along with the baking soda. Make sure everything is moist, but it doesn't need to be overly mixed at this point.
Knead on a well-floured surface for about 10-12 turns. Shape into a round loaf.
Put in greased casserole dish and brush with egg yolk.
Slash an "X" in the top of the dough, and bake for one hour at 375° F.