Put the flour with the baking soda in a large bowl with a lid. Mix the yeast with the sugar until the yeast becomes liquid. Add to the flour and knead vigorously with the herbs, warm milk and 3 - 4 pieces of margarine. When the dough is smooth, let it rest in a warm place.
After about 30-45 minutes, the dough should have doubled. Knead again with floured hands and divide into 3 equal parts. Shape the pieces into long strands and braid them into a braid. Brush the yeast plait with the egg yolk and bake for about 30 minutes at 200 degrees.