To make the starter: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Mix the starter ingredients together in a medium-sized bowl, cover, and let rest at room temperature overnight., To make the dough: Combine the starter with the remaining dough ingredients, mixing and kneading to make a soft, smooth dough. Cover and let rise for 1 hour. Deflate the dough, fold it in thirds, turn it over, and return it to the bowl. Cover and let rise for 2 more hours., Deflate the risen dough, round it into a ball, cover, and let it rest for 10 minutes. After this rest, pat or roll the dough into a 14" round. Place the dough on a parchment-lined 14" round pizza pan (or a large baking sheet), cover with greased plastic or your favorite reusable wrap, and refrigerate overnight., To bake: Remove the dough from the refrigerator and let it rest at room temperature for 30 minutes while you preheat the oven to 350°F. Uncover the dough and brush the top with the beaten egg white. Sprinkle generously with sesame seeds., Bake the bread for 25 to 30 minutes, until it's deep golden brown and the center reads 190°F when measured with a digital thermometer. Remove the bread from the oven and let it cool on a rack., To assemble: Cut the bread in half across its equator to make two 14" rounds. Brush the cut side of each round with 3 tablespoons olive oil or garlic oil. Mix 2 tablespoons olive oil or garlic oil into the chopped olives and spread on the cut side of the bottom round. Layer on the ham, salami, provolone, and mortadella. Cover with the top round. Slice in 2" wide strips, then in 4" pieces to serve., Store any leftovers, wrapped and refrigerated, for up to two days.