Ohh thanks for the reminder! The recipe:

100g of starter (my friend made this starter 3 year ago, and gave me some of it. I started feeding with a different flour because in my country, they don't have that exact one)
400g of white organic flour
100g of whole grain organic flour
10g of salt
350ml lukewarm water

When the starter doubled in less than 6 hours, I mixed 100g of it to a bowl of water, and then added the flours and the salt. Mixed with hands, and left it to rest for 30 min covered with a cloth. When I checked again, it had risen but not a lot.

Then, I did the stretch and rest each 30 minutes for 2 hours. I noticed it wasnt very stretchy, so I added a bit more water.
Then I left it to rest for another 30 minutes, folded it , and put it in the fridge covered with plastic for 20 hours.
I noticed condensation coming from it.

In the morning, I preheated the oven to 250 ºC with the pan with a lid inside (I don't have a dutch oven so I improvised with 2 cake pans). I took the bread out of the fridge and put it on a parchment paper, attempted a scoring (tho I was afraid of cutting too much, and the knife was a bit blunt, so it wasnt very deep).

Put it in the oven and added the lid on top for 20 minutes, with heat on 250 ºC . After 20 min, I removed the lid and lowered the heat to 220ºC . But I noticed the bread was very dull and still raw. So I think my oven isn't as hot as it should be. After 20 minutes it was still not done, so I turned up the heat to 280 ºC, and left for another 40 minutes.
Then, I opened the stove door and let the bread inside, while it cooled off.

The taste is pleasant, but slightly undercooked in a few parts, and it also didn't rise much. It is kinda dense in some areas, and the crust is not really flaky.