1
Mix all the ingredients the night before (you will prepare the dough in the morning).
2
Combine the water, psyllium husk flakes, and honey. Mix well and set aside for 5 minutes (it will have a jelly-like texture). Now add the preferment to the wet mix. Combine with a wooden spoon.
3
Mix all the dry ingredients in a glass bowl. Add the wet mix to the dry ingredients, incorporate as much as possible with a wooden spoon, then start mixing with your hand until the dough is homogeneous and has no lumps (soft and sticky).
4
Mix with a plastic dough scraper, scraping the dough from the sides of the bowl, and folding it into the center. Rotate the bowl and repeat with the same movement, for about 1 minute. Cover the bowl and let it rest for about 10 minutes.
5
Add the olive oil, mix with the hands, so the oil is well incorporated, then repeat the folding method using the plastic scraper. Let the dough rest for 30 minutes.
6
Transfer the dough to the pan, drizzle olive oil, and spread it out with your fingers. Cover the pan with a damp towel, put everything in a plastic bag, tighten it and let it proof/ferment for about 1h 30 minutes (at 72F).
7
Preheat the oven to 240C/465F for at least 40 minutes before baking. Garnish the dough with olives, rosemary, and sea salt flakes. Turn the heat down to 230C/450F and bake for 25 minutes.
8
Rest for 10 minutes, slice into squares, and serve. The focaccia can also be frozen.