In a large mixing bowl add the 3 cups of flour and warm water and mix until fully incorporated. Let the mixture rest for 45 minutes.
Add the additional 1/2 cup of flour, the starter and the salt to the mixture and knead for 8 minutes. Do not add more flour.
With wet hands, remove the dough and place in a large, greased bowl. Cover, place in a warm spot and allow the dough to rise for 3 hours. Every hour of the rise time, stretch and fold the dough around the edges into the center of the dough.
Remove the dough from the bowl onto a lightly floured surface and stretch and fold the dough again. Do not knead the dough, just place the stretched dough into the center. Turn the dough over and lightly flour the top of the dough. With your fingertips together, pull the dough towards you to create a tighter ball shape. Turn the dough a quarter turn and pull the dough towards you again. Repeat until you have gone around a full turn.
Place the dough into a large, parchment lined bowl with a flour dusting. Cover and let the dough rise in a warm spot for 2 more hours.
During the last 30 minutes of the rise time, place a dutch oven inside the oven and preheat to 450 degrees F.
After 2 hours, score/slash the top of the dough. Carefully remove the lid to the dutch oven. Using the parchment paper, lift the dough out of the bowl and gently place the dough, with the parchment paper, inside the dutch oven. Do not drop it in or you will flatten your loaf. Place the lid back on and bake for 20 minutes.
Carefully remove the lid from the dutch oven, lower the oven temperature to 375 degrees F and bake an additional 10-20 minutes until the top is browned and the internal temperature is 190 degrees F.
Remove the loaf from the dutch oven and allow to cool. Slice and enjoy!
If you do not have a dutch oven, you can bake on a baking stone of pan. If you do this, add a cookie sheet on a lower rack below the stone/pan and allow it to preheat just like the dutch oven. When you put the loaf in the oven to bake, pour a cup of water into the cookie sheet to produce steam during baking. This will produce the crunchy crust that is so good in this loaf.