In a small bowl, combine the warm water, sugar, and yeast. Stir gently and let it sit for about 5-10 minutes until frothy.

In a large mixing bowl, combine the flour and salt. Make a well in the center and pour in the yeast mixture and olive oil.

Mix until a shaggy dough forms. Turn the dough out onto a floured surface and knead for about 8-10 minutes until smooth and elastic.

Place the dough in a lightly greased bowl, cover it with a damp cloth, and let it rise in a warm place for about 1-2 hours or until doubled in size.

Preheat your oven to 425°F (220°C).

Once the dough has risen, punch it down and transfer it to a greased baking sheet or a parchment-lined baking pan. Stretch and shape the dough into a rectangle or circle, about 1/2 inch thick.

Use your fingers to make dimples all over the surface of the dough. Drizzle olive oil over the top and sprinkle with chopped rosemary and coarse sea salt.

Allow the dough to rise again for about 20-30 minutes.

Bake in the preheated oven for 20-25 minutes, or until the focaccia is golden brown and sounds hollow when tapped on the bottom.

Remove from the oven and let it cool slightly before slicing. Enjoy warm or at room temperature.