1. Preparation
In a small bowl, combine 1 tablespoon of sugar and 1 cup of warm water. Sprinkle 2 teaspoons of active dry yeast on top and let it sit for 10 minutes until foamy.
In a large mixing bowl, mix 4 cups of all-purpose flour and 2 teaspoons of salt until well combined.
Once the yeast mixture is foamy, add it to the flour mixture along with ¼ cup of olive oil. Stir until a shaggy dough forms.
Transfer the dough onto a floured surface and knead for about 5-7 minutes until smooth and elastic.
Grease a large bowl with olive oil, place the dough in the bowl, cover it with a damp cloth and let it rise in a warm place for about 1 hour or until doubled in size.
2. Shaping and Second Rise
Once the dough has risen, punch it down to release the air. Turn it out onto a greased baking sheet.
Gently stretch and press the dough into a rectangle or circle, about 1 inch thick.
Use your fingers to create dimples all over the top of the dough.
Drizzle with more olive oil and sprinkle with 1-2 teaspoons of coarse sea salt and fresh rosemary.
Cover the dough again with a damp cloth and let it rise for another 30 minutes.
3. Baking
Preheat your oven to 425°F (220°C).
Bake the focaccia in the preheated oven for 20-25 minutes or until golden brown.
Remove from the oven and let it cool on a wire rack for 10 minutes before slicing.