Gruyère-Stuffed Crusty Loaves

To make the starter: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Mix the 1 1/4 cups flour, salt, yeast, and 1/2 cup water in a medium-sized bowl. Mix until well combined; the starter will be stiff, not soft/liquid. Cover and let rest overnight at room temperature (65°F to 75°F is ideal); it'll become bubbly., To make the dough: Combine the risen starter with the water, salt, flour, flavor (if you're using it), and yeast. Knead — by hand, mixer, or bread machine set on the dough cycle — to make a smooth dough., Place the dough in a lightly greased bowl, cover, and let it rise until it's nearly doubled in bulk, about 1 1/2 to 2 hours., Gently deflate the dough, and turn it out onto a lightly floured surface, or a piece of parchment. Pat and stretch it into a 3/4"-thick rectangle, about 9" x 12". Spritz with water (or brush with garlic oil), and sprinkle with the grated cheese (and Pizza Seasoning, if you're using it)., Starting with a long side, roll the dough into a log, pinching the seam and the ends to seal. The cheese will try to fall out; that's OK, just try to enclose as much as possible, then pack any errant cheese into the ends before sealing., Place the log, seam-side down, on a lightly floured or lightly oiled surface (or leave it on the parchment and place the parchment on a baking sheet, for easiest transport)., Gently cut the log into four crosswise slices, for mini-breads; or simply cut the dough in half, for two normal-sized loaves. A large sharp knife or serrated knife works well here. If for some reason you fail to cut all the way through the dough at the bottom, simply take a pair of scissors and snip through the dough., Place the loaves on one (for two loaves) or two (for four mini-loaves) lightly greased or parchment-lined baking sheets, cut side up., Cover the breads and let rise until they're puffy though not doubled in bulk, about 1 to 1 1/2 hours. Towards the end of the rising time, preheat the oven to 425°F. If you're baking two loaves, position a rack in the center of the oven. If you're baking four loaves, place two racks towards the center of the oven with just enough room in between to accommodate the rising loaves., Spread the loaves open a bit at the top, if necessary, to more fully expose the cheese. Spritz with warm water., Bake for 25 to 35 minutes (for the mini-loaves), or 35 to 40 minutes (for the full-sized loaves), or until the cheese is melted and the loaves are a deep golden brown. If you're baking four loaves on two pans, rotate the pans halfway through the baking time: top to bottom, bottom to top. Remove the pans from the oven, and cool the bread right on the pans. Bread is best served warm., Store any leftovers, well-wrapped, for a day or so in the refrigerator; freeze for longer storage (up to 4 weeks). Reheat bread before serving; wrap in foil, and warm in a preheated 350°F oven for 25 to 30 minutes, or until heated through. Bread that's been frozen can be taken right from the freezer, wrapped in foil (if it's not already), and put into a 350°F oven. It'll be nicely warmed in 45 to 50 minutes.