In a small bowl, combine the warm water, sugar, and active dry yeast. Stir gently, then let the mixture sit for about 5 minutes or until it becomes frothy, indicating the yeast is active.
In a large mixing bowl, whisk together the flour and salt. Make a well in the center of the flour mixture, then pour in the yeast mixture and the olive oil.
Using a wooden spoon or your hands, mix until a cohesive dough starts to form. Transfer the dough to a floured surface and knead for approximately 5 minutes, or until it is smooth and elastic.
Lightly oil a clean bowl, place the kneaded dough inside, and cover it with a damp cloth. Set the bowl in a warm area to rise for about 1 hour, or until the dough has doubled in size.
Preheat your oven to 425°F (220°C) while waiting for the dough to rise.
Once the dough has risen, punch it down gently to release any air bubbles. Transfer it to a greased baking sheet or a generously oiled cast-iron skillet.
With your fingertips, gently stretch and press the dough into your desired shape—either a rectangle for a baking sheet or a circle if you're using a skillet.
Use your fingertips to make dimples all over the surface of the dough. Drizzle a little extra olive oil over the top, ensuring it seeps into the dimples. Evenly distribute the chopped rosemary and thin garlic slices over the dough.
Finish by sprinkling flaky sea salt generously over the top of the focaccia.
Allow the dough to rest for an additional 20-30 minutes—not only will it puff up slightly, but this step will help achieve a light texture.
Place the focaccia in the preheated oven and bake for 20-25 minutes, or until the top is golden brown and the fragrant aroma wafts through your kitchen.
Once baked, remove the focaccia from the oven and let it cool for a few minutes before slicing into pieces and serving.
Notes
Serve warm with olive oil for dipping and garnish with fresh rosemary.