Whisk the flour and the salt together in a bowl
450 g bread flour, 9 g salt
In the stand mixer bowl, add the starter, mashed potato, olive oil and water
180 g sourdough starter, 153 g potato, 45 g olive oil plus extra for glass dish and baking tray (2Tbls), 315 g water
Using the stick blender, blitz the wet ingredients together until frothy
Place the mixer bowl in the stand mixer and attach the dough hook
Add the flour and salt mix to the wet ingredients and mix on med speed for about 15 minutes. Tip dough into glass dish sprinkled with olive oil. Cover loosely and leave for 1-2 hours to rest.
Cover tightly with lid and store in fridge for 12 hours
Remove dough from fridge and tip into oiled baking tray - using the heal of your palm, stretch and pull dough to fit the baking tray. Place in the off oven with the light on and a bowl of hot water on the bottom shelf for 2 hours to double in size.
Mix the toppings together in a glass dish and let stand whilst waiting for the dough the double in size
4 sprigs rosemary, 40 ml olive oil plus, 40 ml water, 2 pinch sea salt flakes, 1 chilli, 2 tbsp preserved lemon
Poise your fingers into a piano playing position, dip them into the rosemary olive oil water mix and then into the dough creating little pockets for the mixed oil to collect. Once this is done there will be leftover herbs in the dish scatter these evenly over the focaccia and rest for an additional 30-60 minutes. This dough will be bubbly. Put oven on to 190ºC whilst waiting for dough the proof.
Place baking tray in oven and bake for 35-40 minutes until golden brown. If you prefer a pale focaccia bake for less time. Check after 25 minutes to see if this is the colour you prefer.
Serve with any of your favourite Italian dishes or a bowl of soup