Proof the yeast: In a small bowl, add warm water that is about 110°F. Sprinkle the yeast on top of the water. Add in the sugar. Give it a quick stir to combine. Let the yeast sit for 5-10 minutes, until it is foamy and starts to activate (If you’re doing the dough in a stand mixer, do this step in the bowl of your mixer. if you’re doing the dough by hand, do this step in a large mixing bowl).
Whisk in the olive oil: When yeast is ready, whisk in the olive oil; set aside.
Flour + Salt: In a large mixing bowl, add the flour and 3 teaspoons of salt; whisk together.
Make the focaccia dough: (see instructions below to make by hand) If making dough in your stand mixer, use a rubber spatula to mix half the flour mixture with the yeast mixture. Attach the dough hook to your mixer and add in the rest of the flour mixture. Mix on low speed for about three minutes. If dough seems too sticky and doesn't pull from the sides of the bowl, add in some more flour, a tablespoon at a time, and mix
Form the dough into a ball: Spread some olive oil in a large bowl (I always use a glass bowl), rubbing it around the bottom and sides of the bowl. Remove the dough from the bowl. Place the dough in the bowl and swish the dough around the bottom of the bowl. Then flip the dough over so all of the dough is covered in a light film of oil.
Cover the bowl: Cover the bowl with plastic wrap or a clean kitchen towel. Set the bowl in a draft-free part of your kitchen and let it rise at room temperature until doubled in size (about 1-1 1/2 hours).
Second rise of the focaccia: Prep a large rimmed baking sheet (18-by-13) with parchment paper. You could use a jelly roll pan or use a round baking pan. Spread some olive oil on the parchment paper.
Spread dough into the pan: Remove the dough from the bowl and place it on a parchment lined baking sheet. Pat and press the dough gently until the dough fills the pan completely. If the dough resists, let it rest for a few minutes before continuing (sometimes the dough can be moody). Be patient. It may take a few minutes to be ready to be gently prodded into shape. It may look small at first and then will start to expand as it's sitting in the pan. Once you got it spread out, cover the dough with a piece of plastic wrap (or a clean kitchen towel) and let it rise again until doubled in size (about 40-60 minutes).
Heat the oven: Set a rack in the lower third of the oven and preheat to 425 F.
Dimple the dough: When the dough has doubled in size, remove the plastic wrap. Dimple the surface of the risen focaccia using your fingertips.
Brush on the remaining olive oil: Brush the rest of the olive oil all over the surface of the dough. Sprinkle on the sea salt (Add the amount of salt you prefer. We like it a little saltier). Sprinkle on the chopped rosemary.
Bake focaccia: Bake for 25-30 minutes, or until golden brown and puffed around the edges. You could use a metal spatula to check that the bottom crust nice, crisp and golden brown.
Remove from oven: Lift the focaccia from the pan with the parchment paper edges onto a cutting board. While the focaccia is very hot right out of the oven, brush or drizzle on some more extra-virgin olive oil. Let it cool down a little bit before you cut and serve (we never let it cool down…everyone is ready to get their first piece while it’s piping hot!). Enjoy!