I don't exactly make tortillas, but savory sourdough pancakes are part of my typical repertoire. I start with sourdough starter, add more water and flour and an egg, then get creative: grated raw root vegetables, sauteed onions or other vegetables, leftover grains, grated cheese, sometimes even meat. Then I leave the batter to ferment 12-24 hours, till good and bubbly, then make it into pancakes, which I generally serve with a yogurt-hot sauce blend. Yum!