Measure 1/2 cup sourdough starter into a bowl and add 1 cup water. Mix well.
In a second bowl, add 3 cups bread flour and the salt. Whisk well to distribute the salt with the flour.
Pour the starter mixture into the bowl with the flour and salt.
Use your hand to mix well in a roughly formed ball.
Cover the bowl with a towel and allow to rest for 30 minutes.
Remove the ball from the bowl and fold over a number of times and then form into a round. (See video)
Cover a baking sheet with parchment paper and dust with flour. Place round on the covered baking sheet. Dust the top of the dough with flour, cover with a cloth, and allow to rise 1 1/2 - 2 hours until double in size.
While the dough is rising, place your Dutch oven with lid into your cooking oven and preheat oven to 500 degrees Fahrenheit.
When the dough has doubled in size on your covered baking sheet, remove your Dutch oven from your cooking oven. Your Dutch oven will be hot, so use potholders and be careful. Remove the Dutch oven lid. Lift parchment paper with dough on it and place the paper and dough into your Dutch oven. Place the lid back on and transfer your Dutch oven back into your cooking oven.
Bake bread in your covered Dutch oven for 30 minutes.
Next, remove lid from your Dutch oven and allow bread to continue baking inside your cooking oven for 5-10 minutes more until golden brown.
Using pot holders, remove your Dutch oven from your cooking oven, and then continuing to use pot holders, remove bread from your Dutch oven by lifting it out using the parchment paper.
Transfer bread on parchment paper to a cooling rack.
Allow bread to cool, then slice with a serrated knife, and enjoy with butter.