The evening before you want to make the focaccia bread, put the yeast and warm water in a medium bowl and whisk to dissolve. Then add the flour and stir using a wooden spoon until thoroughly combined with no lumps remaining.
Cover with clingfilm and leave on the work surface to rest overnight for ideally 10-15 hours until bubbly and doubled in size.
When you are ready to make the focaccia, decant the poolish into a stand mixer fitted with a dough hook. Then add the remainder of the dough ingredients. Mix for about 10-12 minutes on medium speed until the dough is smooth and elastic. Keep in mind focaccia dough is very wet so don’t be alarmed at this.
Decant the dough in a large clean bowl, well oiled with extra virgin olive oil. Cover with cling film and leave to rest and rise for approx 2 hours or until doubled in size. If you leave the dough close to a warn oven it will speed up the process,
When your dough has sufficiently risen, grease your two baking tins well with olive oil.
Divide the dough into two equal pieces if making two, you may need to flour or oil your hands to make this easier.
Gently spread the dough out with your fingers until it reaches the edge of the tin.
Cover again with clingfilm and leave to rise in a warm place for 1-2 hours. It may take longer than expected if the temperature in the room is cooler.
You want a really light, voluminous dough here so be patient.
Pre-heat your oven to 220 degrees Celsius.
Mix the oil and water in a small bowl using a whisk until it emulsifies.
Oil your fingers and press them into the focaccia dough to create the classic pattern of dimples and holes.
Pour over the emulsion, sprinkle liberally with the flaky salt and the sprigs of rosemary. You can add any other flavours you like on top, cherry tomatoes and capers also work very well.
Bake in the centre of your hot pre-heated oven for about 20 30 minutes until well risen and a deep golden brown.
When the focaccia comes out of the oven drizzle with a little more extra virgin olive oil, leave to cool for 5 or so minutes in the tin and then turn out, cut into squares and enjoy. It’s best while warm and it also freezes well for re- heating another day. Also its great cut horizontally for the tastiest sandwich bread ever.