Step 1

In the morning–around the time you’d usually feed your sourdough starter–add all-purpose flour, bread flour, 344g water (reserve remaining 50g for later), salt and 94g mature sourdough starter to a large bowl. Mix by hand or in the bowl of a stand mixer with the dough hook attachment on low speed just until the mixture forms a dough. Continue to knead the dough by hand, or in a stand mixer on medium speed, until the dough becomes smooth and elastic (about 5 minutes by hand, 3 to 4 minutes in a stand mixer).

Step 2

Slowly add remaining 50g water to dough, kneading or mixing on low speed as you go. Continue to knead or mix on medium speed until mixture re-forms into a soft, smooth mass of dough. Drizzle in olive oil, kneading or mixing on low speed as you go. Mix the dough and oil together until everything is fully combined and the dough is smooth and elastic (about 3 to 5 minutes by hand, 1 to 2 minutes in a stand mixer).

Step 3

Use a silicone spatula or a silicone dough scraper to scrape dough into a clean large bowl (the dough will be very slack and soft, so don’t try to pick it up/transfer it with your hands). Cover bowl with plastic wrap and let rest in a warm place for 30 minutes (I placed my bowl in the oven, turned off, with the oven light on).

Step 4

After 30 minutes have elapsed, uncover bowl. Perform one set of stretch and folds (see the “Bulk Fermentation” section of my sourdough bread recipe for a written explanation + link to a video on what this looks like!), then cover the bowl again and return it to its resting place. Repeat this step (one set of stretch and folds) every 30 minutes over the course of 2 hours. You will end up giving the dough 4 sets of stretches and folds total.

Step 5

After the 2 hours have elapsed, transfer the dough gently (so as not to disturb any bubbles that may have formed) to a well-oiled 13×9-inch baking pan (and by “well-oiled,” I mean at least 1-2 tablespoons of olive oil so the dough doesn’t stick to the pan during baking). Cover the pan with plastic wrap and let the dough rest 2 hours, uncovering every 30 minutes to gently stretch the dough with wet hands to the corners of the pan (it will take the entire 2 hours for the dough to relax and stretch, but don’t worry–it will get there!).

Step 6

After these 2 hours have elapsed, leave the dough covered and untouched for another 2 hours in its warm place. This is when the dough will puff up and develop more bubbles. About 30 minutes before you plan to bake the bread, place an oven rack in the bottom third of the oven and heat your oven to 450°F (if you have the dough proofing in the oven, TAKE IT OUT before preheating!).

Step 7

Before baking, use wet fingers to dimple the top of the dough all over, pressing all the way to the bottom of the pan. Drizzle about 1-2 tablespoons olive oil evenly on top of dough, then sprinkle with desired toppings.

Step 8

Bake focaccia until deep golden brown on top, about 30 to 40 minutes, rotating pan halfway through baking. Cool 5 minutes in baking pan, then carefully transfer to a cooling rack. Serve warm or at room temperature.

Step 9

Store bread in an airtight container at room temperature up to 3 days.