In a large mixing bowl, combine sourdough starter, water, dry milk, yeast, salt, and olive oil. Add 2 cups flour and mix to make a soft dough. Add olives, rosemary, and oregano, adding the rest of the flour as needed to make a nice dough. Transfer dough to a lightly greased bowl and cover. Let rise for 60 minutes until double.
Gently deflate the dough and shape into two 8" x 10" ovals. Lay out on a greased parchment paper. Cut decorative slits in the bread from top to bottom with some cooking shears. Pull the dough apart where the slits are, to allow for rising.
In a small bowl, combine olive oil and garlic. Brush garlic oil over bread and sprinkle with sea salt. Cover and let rise for 30-45 minutes. Preheat oven to 400 degrees. With a pizza peel, transfer bread to a hot baking stone. Bake for 15-18 minutes until golden brown. Remove bread from the oven and transfer to a wire rack to cool. Makes 2 large flatbread.
Notes
*You may use a convection oven setting for this recipe. If you do so, you may want to decrease the baking time by 2-3 minutes.