Preheat oven to 375°F (190°C).

Sift together the flour, sugar, salt, and baking powder in a large bowl.

Stir in the caraway seeds and raisins.

Cut in the butter or margarine until the mixture resembles coarse crumbs.

In a separate bowl, whisk together the buttermilk, egg, and baking soda.

Add the wet ingredients to the dry ingredients and stir until just combined. Do not overmix.

Turn the dough out onto a lightly floured surface and knead gently a few times to form a round loaf.

Place the loaf on a baking sheet.

Cut a deep cross into the top of the loaf.

Brush with egg yolk or cream (optional).

Bake for 45 minutes, or until a toothpick inserted into the center comes out clean.

Let cool slightly before slicing and serving.