Prepare the Dough

1. Mix the Dry Ingredients: In a large mixing bowl, combine the flour, salt, and yeast.
2. Add Water and Oil: Gradually pour in the warm water and 1/4 cup of olive oil. Mix until a sticky dough forms.
3. Knead the Dough: Transfer the dough to a lightly floured surface and knead for about 5-7 minutes until smooth and elastic.
4. First Rise: Place the dough in a lightly oiled bowl, cover with a kitchen towel, and let it rise in a warm place for 1 hour or until doubled in size.

Shape the Dough

1. Prepare the Baking Pan: Grease a 9×13-inch baking pan with olive oil.
2. Shape and Rest: Transfer the dough to the prepared pan and gently press it out to fit the shape of the pan. Let it rest for 15-20 minutes.
3. Dimple the Dough: Use your fingers to press dimples all over the surface of the dough.

Add Toppings and Bake

1. Preheat the Oven: Preheat your oven to 400°F (200°C).
2. Add Rosemary and Olive Oil: Drizzle 3 tbsp of olive oil over the dough, making sure it settles into the dimples. Sprinkle with chopped rosemary and coarse sea salt.
3. Bake: Bake for 25-30 minutes, or until the focaccia is golden brown and crisp around the edges.
4. Cool and Serve: Remove from the oven and let cool for 10 minutes before slicing and serving.