In a small bowl or measuring cup, add the yeast and sugar to the lukewarm water. Allow to rest for 5-10 minutes, or until yeast is foamy/bubbly.
In a large mixing bowl, whisk together the flour, salt, and dried herbs. Add the sourdough starter and the yeast mixture, then add the wet ingredients to the dry and stir until combined. Dough will be very sticky!
Cover the bowl with a tea towel and set in a warm place to rise for an hour.
Preheat the oven to 425 degrees. Grease a 13x9-inch baking dish with the butter.
Gently stir down the risen dough. Pour the dough into the prepared baking dish. Drizzle the top of the dough with the olive oil, then use your hands to gently spread the dough to cover the bottom of the pan. Press your fingertips into the dough to the bottom of the pan, creating dimples all over the surface of the dough. Sprinkle the surface of the dough with sea salt.
Cover with a tea towel and allow to rise for 20-30 minutes, or until puffy.
Bake for 15 minutes. Reduce heat to 375 degrees and continue baking for an additional 15-17 minutes or until golden brown.
Remove bread from oven and turn out onto a cooling rack. Let cool for 10 minutes before slicing.