Mix the 3 cups of flour and 1 tsp. of salt in a medium sized bowl.
Measure the 1 1/2 cups of water and 1/2 cup of starter in a separate bowl and mix thoroughly.*
Add the water mixture to the flour mixture and mix thoroughly with your hands or a sturdy spoon. You may use a bread mixer, if you prefer. Mix until the dough clears the side of the bowl.
If you prefer to knead the dough, do so now for 8-10 minutes**. (I recommend you stretch and fold the dough for a quintessential sourdough look and texture.)
If you decide to stretch and fold the dough instead of knead, allow the dough to rest for 30 minutes to an hour. Perform your first stretch and fold. Allow the dough another 30-60 minutes, and perform your second stretch and fold. You may do one more stretch and fold, or simply cover the dough and follow the next steps. Instructions on stretching and folding the dough are below in the notes section, as well as in the body of the article.
Form the dough into a ball and place it back in the bowl. Cover the bowl and set it to ferment undisturbed for at least 6 hours.
Uncover the dough and remove it from the bowl with wet or oiled hands to prevent sticking.
Shape the dough in your hands or on a clean wet/oiled surface into a rectangle. Roll up the rectangle to loaf-shape - it looks a bit like a dough baby. Place your dough into an oiled or parchment-lined bread pan.
Invert an oiled bread pan over the top of your bread dough pan. Leave to rise until roughly doubled in size. This usually takes 1-2 hours, depending on the ambient temperature.
Remove the inverted pan and use a pair of scissors to cut 3-6 slashes in the top of your dough. Replace the inverted pan.
Place your bread with the inverted bread pan on top of it into a cold oven. Heat to 425°F/218°C and bake for 35 minutes.
Reduce heat to 400°F/204°C and bake for another 20-25 minutes. The bread should sound hollow when you tap on it. If you happen to have a thermometer, it should read between 205-210°F (96-99°C) when baked completely.
Remove the bread from the oven and turn it out onto a cooling rack. Allow the bread to cool completely (12-24) hours before cutting into it, if you manage to restrain yourself.**
Keep in a covered container at room temperature for 7-10 days. If the container sweats, pop the lid and allow the loaf to dry a bit more. You may also freeze or refrigerate.