Uncover the bowl of sponge. Add1 ½ cups all-purpose flour, ¼ cup of olive oil and 1 teaspoon of fine sea salt to the bowl with the sponge. You will use the remaining ½ cup of flour to knead the dough.
Mix the dough ingredients with the sourdough sponge until the dough is too stiff to mix with the spoon and most of the flour is mixed into the sponge.
Kneading the dough in the bowl, dusting with the reserved half cup of flour for about 5 minutes. The focaccia dough should feel soft and mostly smooth.
Form the kneaded dough into a tight ball and place the ball into the bowl. Drizzle with olive oil to cover the dough.
Cover with plastic wrap or a lint free towel and allow to rise until doubled, about 1-½ to 2 hours.
Prepare the baking sheet pouring ¼ of olive oil into the center of the pan, swirling to cover the bottom and sides.. (see notes)
Once the dough has risen until doubled in size gently punch dough down.
Place the ball of dough into the center of the oiled baking sheet.
With the heal of your hand your work the dough out from the center of the pan into the corners until it fills the pan and is pushed up onto the sides of the pan forming a lip. If the dough is very elastic and pulling away, allow the dough to rest about five minutes and then continue.
Cover with the pan with a lint free kitchen towel and allow the focaccia dough to rise in a warm area until roughly doubled in size, about an hour.
Preheat oven to 450 degrees Fahrenheit.
Once dough has risen, gently dock the dough with your finger tips all over the top, leaving little impressions in the soft dough. If the dough is a little dry on top, drizzle a bit more extra virgin olive oil over the top.
Sprinkle the top with coarse sea salt and any other toppings you are using before baking.
Bake for 20 minutes in the preheated oven or until the top is golden brown.
Remove from the oven and allow to cool in the pan on a wire rack for five minutes. After 5 minutes remove the flat bread from the pan using a wide spatula and transfer to the wire rack to cool completely before cuttings.
Cut into squares or bread sticks and serve warm.