In a large bowl whisk together flour and fine sea salt. Make a well in the center and add the foamy yeast mixture and 2 tablespoons extra-virgin olive oil. Stir with a wooden spoon or dough scraper until a shaggy dough forms.

Knead

Turn the dough onto a lightly floured surface and knead 6–8 minutes until smooth and elastic (or use a stand mixer with dough hook on medium for 5 minutes). Add small spritzs of water or a tablespoon of flour if needed to reach a soft slightly tacky consistency.

First rise

Lightly oil a clean bowl with 1 tablespoon olive oil, place the dough inside, turning to coat. Cover with plastic wrap or a damp towel and let rise in a warm draft-free spot until doubled, about 1 to 1¼ hours.

Assemble & Bake Focaccia

Prepare pan

Generously oil a 9x13-inch baking pan with the remaining 1 tablespoon olive oil and a tablespoon of extra-virgin olive oil (from the 4 tbs listed). Punch down the risen dough and press or stretch it into the oiled pan, working it to the corners. If dough resists, let rest 10 minutes then continue.

Dimple dough

Using your fingertips, press dimples all over the surface of the dough. Drizzle the remaining 2 tablespoons extra-virgin olive oil evenly over the top and sprinkle with garlic powder and half of the chopped rosemary.

Second rise

Cover loosely and let the dough rise again for 20–30 minutes until slightly puffy.

Pre-bake

Preheat the oven to 425°F (220°C). Bake the plain focaccia base for 8 minutes to set the crust slightly — this prevents over-sogginess from the filling.

Filling & Finishing Bake

Add fillings

Remove the par-baked focaccia from the oven. Layer the provolone slices evenly over the crust, followed by the turkey slices distributed in an even layer. Scatter shredded mozzarella, chopped sun-dried tomatoes, and thinly sliced red onion evenly over the top. Finish with the remaining chopped rosemary, sea salt flakes and coarsely ground black pepper.

Bake until golden and melty

Return the focaccia to the oven and bake 10–12 minutes more, until cheese is melted and edges are golden-brown. If you prefer a crisper top, broil on high for 1–2 minutes while watching closely.

Rest and slice

Remove from oven and let rest 5 minutes. Drizzle a little extra-virgin olive oil over slices if desired, then cut into 8 rectangular pieces.

Serve

Serve warm topped with mixed baby greens and a drizzle of balsamic glaze if using. The focaccia can also be cooled, wrapped and refrigerated for up to 3 days or frozen for up to 1 month. Reheat in a 350°F (175°C) oven until warmed through.