In a large bowl, combine 330g warm water with 150g of active sourdough starter until mostly combined.

Add 500g bread flour and 10g salt to the bowl and mix until a shaggy dough forms. Knead the dough with your hands until all the shaggy bits are incorporated.

Cover the bowl and set aside for 45 - 60 minutes.

Uncover the bowl and using damp hands, grab the dough and gently pull it until the flap is long enough to fold over itself, then fold the flap, rotate the bowl 90 degrees, and repeat 4 times.

Recover the bowl, and set it aside for 30 minutes, then repeat the stretch and fold process at least 3 more times over the next 2 hours.

Complete one final stretch and fold, then cover the bowl and set aside for 2 hours to bulk ferment. It is important to keep the dough bowl somewhere warm to encourage the microbes to work quickly!

Observe your dough, at this point, the dough should have risen in the bowl, and have a smooth surface with visible bubbles. If the dough is domed in the bowl it is ready to work with, if the dough is flat it may need more time in the bulk ferment.

Lightly flour the work surface and use a bowl scraper to turn the dough out onto the floured surface. Try to get the smooth top face down so that the sticky underside is on top facing you, this will make shaping the dough easier.

Fold the edges into the middle, alternating sides as though lacing the dough together. Then starting from the top, fold the dough into thirds as you would a letter, but pull the bottom all the way around to flip the dough so the seam is facing downward. Stop there if making a batard, or tuck the long ends underneath to create a boule.

Dust the top of your boule or batard with rice flour, then use a bench scraper to pick up the dough, flip the dough, and place it upside down, or seam side up, into a banneton to prove.

Cover the banneton either using a damp kitchen towel or a shower cap. During the proving period, the dough will rise and become puffy in the banneton, but it should be watched - as over-proofing can cause the dough to bake up flat. This process will take a different amount of time based on the ambient temperature.

To test the dough, gently poke it and observe how the dough reacts. If the dough feels tight and dense and looks like it hasn't relaxed in the basket, it is likely under proofed. Underproofed dough will resist your poking and spring back almost immediately. If the dough feels airy but still elastic and looks relaxed in the basket, it is properly proofed. Properly proofed dough will be easily poked, and the indent will slowly fill back in but may not even totally recover. Overproofed dough feels sticky and lacks elasticity, it will likely look slack in the basket and your indentation won't rebound.

Place your dutch oven, cloche, or desired baking dish in the oven and preheat to 450f.

Meanwhile, place the banneton in the freezer.

Once the oven is preheated, remove the dough from the freezer and invert the banneton onto a sheet of parchment paper.

Use a lame, sharp knife, or clean razor blade to score the dough.

Carefully remove the dutch oven from the oven, and using the parchment paper as a sling, transfer the sourdough loaf from the counter into the dutch oven.

Bake the dough at 450f covered for 30 minutes and uncovered at 450f for 25-30 minutes, or until the loaf is cooked through. You can test the doneness of the loaf with an instant-read thermometer. Bread is cooked once it reaches 205 - 210 degrees Fahrenheit internal temperature.

Remove baked bread from the dutch oven and transfer it to a wire mesh cooling rack to cool completely before slicing. I like to leave it for at least 2 hours before slicing, as slicing too soon can affect the crumb and texture of your loaf.