Use a stand mixer with a dough hook attachment
Combine the two flours in the bowl.
Make a well in the center of the flours.
Add water, salt and sourdough starter in the well
On speed 1 or 2 combine the dough for 3-4 mins until all ingredients are fully incorporated
On speed 3 or 4 keep mixing the dough for a further 5 mins to get the gluten activated and strengthen the dough. You want it to start collecting around the hook.
Now leave it to rest for 10 mins
At a low speed slowly drizzle the olive oil into the dough, once all the oil has been added, turn up the speed to 2-3 to work the dough.
Transfer the dough to a bulk container to prove. It may seem quite wet but don't be alarmed. The dough will strengthen over the next couple of hours
The next two hours you'll perform 4 stretch and folds every 30 mins. A stretch and fold is when with your dough in front of you, with one hand on your container and the hand "reaches" under the top of dough, you pull up and stretch the dough folding it over the bottom of the container. This is repeated 4 times. It goes like this: top to bottom, left to right bottom to top and right to left
Now liberally grease your oven proof container before transferring the dough into it. There's no need to spread the dough to fit the container as it will naturally expand to fit.
Leave to prove for two hour without performing any stretch and folds.
About 30 mins before the end of proving time turn on your oven to 230C to preheat it
Time to get your chosen topping ready. I chose cherry tomatoes (halved), black olives (pitted and halved), fresh rosemary (chopped) and sea salt flakes
You now need to dimple your focaccia, using wet fingers to create little dimples all over the dough, I worked from top to bottom, drizzle with olive oil and add your topping.
Cook at 230C for about 30 mins until it's beautiful and golden all over
Take it out and leave to cool on a wire rack