In a large bowl, combine flour, soda, and salt and whisk together well. Stir in buttermilk until dough forms. Add caraway and/or raisins or currants and mix throughly.
On a lightly floured surface, knead dough about 30 seconds. Dough will be sticky so just use enough flour to coat your hands. Shape into round loaf.
Place dough on an ungreased baking sheet lined with a piece of parchment paper. With a serrated knife, cut a 1/2” X into the top.
Lightly beat egg yolk and brush over the dough.
Bake 50 to 55 minutes, or until the loaf sounds hollow when tapped on the bottom. Transfer from pan to rack and let cool.