Makes one 25cm x 30cm baking tin
The day before:
1kg bakers flour
900ml warm water (about body temp)
15g dried yeast
25g olive oil
1 bunch rosemary
Make the wet mix with warm water, yeast and olive oil. Weigh dry ingredients and place in a mixer with the dough-hook attachment. Stir the wet mix well and slowly pour into the mixer on a low speed. Continue mixing while increasing the speed of the mixer until it is a smooth batter and you get to high speed. Knead on high for around 5-8 mins until you can hear the dough “slapping” and it has started to come away form the mixing bowl.
Grease a suitable size bowl that will fit in your fridge (bear in mind that the dough will proof and double in size). Transfer the dough to the greased bowl and cover with a damp tea towel. Place in the fridge overnight.
The next day:
Lubricate your baking tin with a combination of salted butter and olive oil. Have a side tray ready with a little squirt of oil to prevent the dough from sticking. Carefully invert the bowl onto the flat tray to tip it out and begin folding the dough over on itself (wet your hands to prevent it from sticking too much to your fingers). Once you’ve kneaded and folded it a few times, place it into the greased baking tin, cover loosely with clingfilm and put it in a warm place to proof and rise. This will take about 1.5 hours.
Finely chop the rosemary. Heat your oven on full fan to 220ºC.
Once it has doubled in size, take the clingfilm off and drizzle with a little bit of olive oil. Sprinkle with the chopped rosemary and give a very generous covering of sea salt flakes.
Place a small steel or oven-proof dish of water into the bottom of the oven, this will help with hydration and crust development.
Just before you are ready to bake, wet your hands again and gently prod the surface of the dough just once, this will give the focaccia it’s signature “dimpling”.
Bake immediately for 20 mins then reduce the oven temperature to 180ºC and remove the pan of water. Bake for a further 15-20 mins until nicely golden and slightly shrunken from the sides of the tray. Remove from oven and using a spatula, gently slide out of the baking tin and onto a cooling rack.