Mix the gluten free flour, sugar, and salt in a large bowl. Dissolve yeast with lukewarm water in a separate bowl.
Combine the starter with dry ingredients, add the yeast mixture, then mix well until the dough holds together.
Add the olive oil, then mix thoroughly until the dough fully absorbs the oil. Shape the dough into a ball, cover it with a cloth, and let it rest for 20 minutes.
Deflate and shape the dough into an oblong on a surface dusted with gluten free flour. Likewise, if you want the bread flatter, press the dough slightly before baking. Rule of thumb, shape the dough according to your Dutch oven size.
Place the dough on parchment paper or a silicon mat covered with a damp cloth. Let it rise for 30 minutes in a warm place while the Dutch oven is preheating in a 220°C (428°F) oven.
Carefully place the dough into the hot Dutch oven. Score a straight line on the dough surface dusted with gluten free flour. Use a bread lame or sharp knife for scoring.
Cover and bake for 20 minutes. Take off the cover and continue baking for another 25-30 minutes until golden brown.
For a darker crust, bake 10 minutes longer for a thick, crunchy crust. (optional)
Remove from the bread from the Dutch oven and let cool on a wire rack before cutting.