Measure/weigh all ingredients.
In the bowl of a stand mixer, pour the water and all of the ripe poolish that you started the day before.
Add the flour, BUT NOT THE SALT or YEAST.
Mix on low speed for 3 minutes to combine the ingredients.
Increase the speed to medium high and beat the mixture for 8-10 minutes. Watch for the dough to transform from a wet batter to a stringy dough. After you begin to see strands, it should pull off the sides of the mixer and come together as a dough. ( roughly 8-10 minutes)
Turn the mixer off and add the yeast and salt. Mix on low to incorporate, then increase the speed to medium and mix for 3 more minutes.
Place the dough in a well oiled container. Cover and let rest for 45 minutes. After 45 minutes stretch and fold the dough in on itself 4 times. ( as if it had 4 sided and you are pulling each side up, and into the center) Flip the dough over so the bottom becomes the top and has a smooth surface.
Allow the dough to rest for and additional 45 minutes.
Preheat your oven to 350°. Spray or oil a 9 by 13 in baking pan.
Pour the dough into the oiled pan and gently push the sides of the dough into the corner of the pan. Use your fingertips to dimple the bread and help to evenly spread it around the pan.
Add the toppings of your choice. ( I like to give the top of the dough an extra drizzle of olive oil and a little sprinkle of sea salt)
Allow to rest for 30 minutes while the oven preheats.
Bake the bread in the center of the oven for 35-45 minutes. Once the bread is baked and cool enough to touch, remove it from the baking pan and place on a cooling rack to prevent the bottom from getting soggy. Cut into 12 squares.
Enjoy your fresh focaccia! To store the bread place in a sealed container of large zip lock.