Step 1: In a large, sturdy 1-gallon zip-top bag, combine the warm water, active dry yeast, and granulated sugar. Gently shake the bag to mix, then let it sit for 5-10 minutes. The mixture should become foamy, indicating the yeast is active.
Step 2: Add the salt and half of the all-purpose flour (about 2 cups) to the bag. Seal the bag, pressing out as much air as possible, then gently mix by squeezing and kneading the bag with your hands until the flour is mostly incorporated.
Step 3: Open the bag and add the remaining flour (2 to 2.5 cups), one cup at a time, mixing after each addition until a shaggy, soft dough forms. You might not need all of the flour; the dough should be slightly sticky but manageable. Do not overmix.
Step 4: Add the olive oil to the bag. Reseal, pressing out air, and continue to gently knead the dough in the bag for about 5-7 minutes. The dough should become smoother and more elastic.
Step 5: Lightly grease the inside of the bag with a little extra olive oil, ensuring the dough is coated. Seal the bag again, leaving some room for expansion. Place the bag in a warm spot and let the dough rise until doubled in size, about 1-1.5 hours, depending on the temperature of your kitchen.
Step 6: Once doubled, gently punch down the dough inside the bag to release the air. Turn the dough out onto a lightly floured surface. Shape it into a round or oblong loaf.
Step 7: Lightly grease a baking sheet or line with parchment paper. Place the shaped dough on the prepared sheet. Cover loosely with plastic wrap or a clean kitchen towel and let it rise for a second time, about 30-45 minutes, or until noticeably puffy. Preheat your oven to 375°F (190°C) during the last 15 minutes of this rise.
Step 8: Just before baking, you can lightly brush the top of the loaf with water or an egg wash for a crispier or shinier crust, respectively. You can also make a few shallow slashes across the top with a sharp knife or bread lame.
Step 9: Bake for 25-35 minutes, or until the crust is golden brown and the internal temperature reaches 200-210°F (93-99°C). If the top is browning too quickly, you can loosely tent it with aluminum foil.
Step 10: Remove the bread from the oven and transfer it to a wire rack to cool completely before slicing. This allows the internal structure to set and prevents a gummy texture.