In a large bowl combine yeast with warm water and sugar. Make sure the water is no hotter than 110°F or else you will kill the yeast. Let the mixture sit for ~5 minutes, the mixture should get bubbly and foam will appear- this is a sign the yeast is working!
Add the flour to the yeast and mix until just combined. The dough will be sticky. Let it sit for 15 minutes then mix in the salt. Waiting to add the salt allows the yeast to work more efficiently in those first 15 minutes.
Once the salt is mixed in well, cover with a light towel and let rise for ~2.5 hours at room temperature.
Divide the dough in half. Shape the dough into two rounded loaves, folding the dough under itself to create a smooth top. If you don't plan to bake both loaves at once, place one dough loaf in an airtight container or ziploc bag and place in the refrigerator to bake later.
Place the loaf onto a parchment lined baking sheet. Let the dough rise again for another 40 minutes. If you are baking your second refrigerated half that you pulled from the refrigerator let the dough rise the for 1.5 hours.
Place a rimmed baking sheet on the bottom rack of your oven. Preheat the oven to 450°F.
Once the dough is done with its second rise, sprinkle with flour and slice the top in several places then place in oven. Pour 1 cup of water into the bottom baking sheet. This will create steam and allow the bread to get a nice crust.
Bake the bread for 25-30 minutes. It should sound hollow and have an internal temperature of 190°F when it’s done. Try to let the bread cool completely before slicing into it or else it can seem undercooked.