In a large measuring cup or medium bowl, stir together the warm water, yeast and sugar. Set aside for 5-10 minutes while the yeast softens and becomes foamy.
Meanwhile, in a large bowl, whisk together the flour and salt.
Make a well in the center of the flour mixture. Pour the water and yeast mixture into the well and use a wooden spoon to combine until a shaggy, rough dough comes together and pulls away from the sides of the bowl. If the dough is too sticky, add more flour in small increments, about 1 tablespoon at a time. If the dough is too dry, add more water, 1 tablespoon at a time.
Transfer the dough to a greased bowl, cover, and leave in a warm spot to rise until doubled in size, about 1 ½ - 2 hours.
Dust a piece of parchment paper with flour. Nudge the dough from the bowl and dump it onto the floured parchment paper. Form the dough into a loose ball by gently folding in the edges. I pat my hands with flour since the dough is very sticky. Don't stress -- this doesn't have to be perfect. We're making a rustic loaf of bread!
Lift the parchment paper and dough into another smaller bowl. Cover the bowl and let rise for about 30-60 minutes.
While the dough is rising for the second time, place a 4-6 quart cast iron Dutch oven with its lid into the oven. Preheat the oven to 470° F.
When the oven reaches temperature and the dough has risen for the second time, carefully remove the Dutch oven from the oven. Transfer the dough from the bowl to the Dutch oven using the edges of the parchment paper to lift the dough. Cover with the lid.
Bake the bread for 30 minutes with the lid on the Dutch oven. Remove the lid and bake for an additional 10-15 minutes until crust is nicely browned (keep a close eye on it).
Remove the bread from the Dutch oven carefully (it’s still very hot) and place on a cooling rack. Allow to cool for at least one hour before slicing.