Starter - The night before making bread: In a medium sized mixing bowl combine flour, water and yeast. Cover with plastic wrap and let the mixture sit out overnight. It should be bubbly and risen the next day.
Dough: In the bowl of a stand mixer fitted with a hook attachment combine starter, flour, water, yeast and salt. Knead together for 10 minutes. The dough will be very sticky - this is normal.
Once the dough has been kneaded, transfer it to a well greased bowl. Cover with plastic wrap or a clean kitchen towel and let rest for 30 minutes.
Once the dough has rested, grease your hands and stretch and fold each side of the dough to the opposing side, about 4 stretches and folds.
Recover with plastic wrap and let rest for another 30 minutes.
Repeat the resting and folding process another 3 times, for a total of 2 hours of rest time and 4 stretches. After the last stretch, let the dough rest for another 30 minutes.
Once rested, turn the dough out onto a clean, lightly floured surface. Press the dough out into a rough square. This does not have to be perfect. Cut the square in half to make 2 loaves.
Grease a baking sheet with baking spray, then transfer the loaves onto the sheet, spacing them about 3" apart. Let the loaves rise for 30 minutes.
While the loaves are rising for the final time, preheat the oven to 350°F. Place a baking sheet filled with water into the bottom rack of the oven. This will create steam while the oven is preheating.
Once the dough has risen, spray well with water, then quickly place into the oven to not let too much steam escape.
Bake for 30 minutes, until golden and baked through. Once baked, remove from the oven and place onto a wire cooling rack. Allow the loaves to cool down before slicing.
Counter. Place the cooled bread in a paper bag and store it for up to 3 days. To keep it fresh for longer, store it in an airtight container away from the sun for up to 5 days.
Fridge. Pop it into an airtight container and refrigerate it for up to a week. Set it on the counter for 10-15 minutes before serving so it's not cold or dense.
Freezer. Wrap the fully cooled loaves with plastic wrap and then in aluminum foil. Place them in a freezer-friendly bag or container. Freeze for up to 3 months. Thaw them overnight in the fridge or over the counter for 2-4 hours.