Morning:

Make the leaven; 50g starter with 50g water and 50g flour.
Mix to combine and let sit covered at room temperature all day.

5:00pm same day:

Add 400g filtered water to a large bowl.
Add the leaven. The leaven should appear to lightly float if it is ready. Stir well.
Add 500g of freshly milled flour. Mix until no dry flour is left. Cover and let sit for 30-45 minutes. (This is called the Autolyse)
In a separate small bowl add 25g room temperature water and 10g salt. Stir to start dissolving the salt.
When the autolyse time is complete, add the salt and water mixture.
Mix with your hands, kneading it until you have a softer, stretchy dough.
Cover and let sit for 30-60 minutes.
Put in the fridge overnight.

The next day:

Remove dough from fridge and let warm up for 1-2 hours.
Pull and fold dough every 30-60 minutes until the dough rises about 20-30%. It should be bubbly and stretchy over time. This phase should take 4-6 hours.

Place dough on a flat surface. Start shaping the loaf using the cap and turn technique to form a round shape. Repeat 1-2 times, until the dough ball forms good surface tension.

Heat oven 480 deg F with dutch oven and lid.

Place dough on parchment paper, coat the dough ball with a little rice flour and score the loaf however you desire.

Bake bread covered for 20 minutes. Decrease oven to 450 deg F, remove lid and continue baking 20 minutes more.

Let the loaf cool completely before cutting.