makes one pan 9- by 13-inches or two 8 or 9-inch rounds; adapted from Maurizio Leo, The Perfect Loaf
Mix together the flours and 425 grams water, let rest/autolyse for 30 minutes.
Add the starter and let rest for 30 minutes. Using the dough hook, mix the dough and drizzle in the 14 grams olive oil and 13 grams salt. Continue with the dough hook on a low-medium speed for 5 minutes. Add up to an additional 25 grams water to make a well-hydrated dough.
Begin 2 hours fermentation with stretch-and-folds every 30 minutes.
Prepare pans with olive oil, about ¼ cup for a 9- by 13-inch pan or 2 tablespoons each for two 8-inch rounds. Cover and begin 4 hours of proofing at room temperature. Every 30 minutes during the first 2 hours, poke and push the dough to the edges of the pan. At the end of proofing, dimple the dough by pressing your fingers to the bottom of the pan. Optionally decorate top with olives, herbs, or toppings of your choice. Drizzle with the remaining olive oil.
Preheat oven to 425°F. Bake focaccia for 30 minutes, until top begins to brown. (Slightly less time one the smaller, rounds, like 25 minutes.)