In a large mixing bowl, combine the all-purpose flour, instant yeast, and sea salt. Whisk thoroughly until all dry ingredients are well blended.
Gradually pour in the warm water and olive oil while stirring with a wooden spoon or spatula. Continue mixing until a sticky dough begins to form.
Lightly flour your hands and knead the dough in the bowl for about 5 minutes, ensuring everything is well combined and the dough develops elasticity. If the dough feels too sticky, sprinkle in a little extra flour as necessary.
Cover the bowl with a damp kitchen towel or plastic wrap to prevent drying out, and place it in a warm location. Allow the dough to rise for about 1 hour, or until it has doubled in size.
Preheat your oven to 425°F (220°C).
Once the dough has risen, gently punch it down with your fist to release the trapped air. Transfer the dough onto a generously oiled baking sheet or a baking sheet lined with parchment paper.
Use your fingers to stretch and spread the dough to fit the size of the sheet, creating dimples across the surface for texture.
Drizzle an ample amount of olive oil over the top of the dough, ensuring it pools in the dimples. Evenly sprinkle the chopped rosemary and flaky sea salt across the surface to enhance flavor.
Allow the dough to rest for an additional 20 minutes, giving it time to puff up slightly.
Bake in the preheated oven for 20-25 minutes, or until the top is beautifully golden brown.
Once baked, remove the focaccia from the oven and let it cool on the baking sheet for a few minutes before slicing. If desired, add a drizzle of olive oil over the top before serving to boost flavor.
Notes
Serve warm, garnished with fresh rosemary and a side of olive oil for dipping.