1Preheat the oven to 350 degrees F. Using a large bowl, combine the yeast, sugar and water; let stand until the yeast begins to get foamy.
2Cut the butter up into 4 pieces and add to the yeast mixture; add half the flour and the salt. Add enough additional flour to make a soft dough.
3When you are no longer able to stir, turn the dough out onto a floured surface and knead for about 10 minutes or until the dough is smooth, shiny and elastic. During the kneading time, use only enough additional flour to keep the dough from sticking to the board.
4Place the dough in a greased bowl and cover with a clean towel or plastic wrap; allow to rise in a warm place until doubled in bulk. (About 90 minutes)
5If using whole olives, drain well and chop coarsely.
6Lightly grease 1 jelly roll pan; sprinkle with cornmeal. Punch the dough ad turn onto a floured work surface. Pat and push into a 14" square; allow the dough to rest for 3 or 4 minutes.
7Scatter the olives or olive salad evenly over the dough; lightly press the olives into the dough. Roll up the dough, working from the long side as for a jelly roll to enclose the olives; place on the prepared pan seam side down. Tuck the ends under to make a smooth surface; pat the loaf to flatten and shape into an oval about 2" thick.
8Cover the loaf with a clean dish towel and leave at room temperature until puffy; about 30 minutes. Uncover the loaf and brush with the beaten egg yolk.
9Place on the lower rack of the oven and bake for 45 minutes or until richly browned. Remove to a cooling rack and cool for at least 10 minutes before slicing.