In a large mixing bowl, combine the flour, salt, and yeast.
Using a stand mixer fitted with the dough hook, turn the mixer to the lowest speed (Speed 1). Slowly add the lukewarm water, about 1/2 cup at a time, until all of the water has been incorporated.
Continue mixing on low speed until the dough comes together. It will be very wet, sticky, and stretchy. This is exactly what you want.
Cover the bowl with a clean kitchen towel and let the dough rise at room temperature for 2 hours, or until doubled in size.
Generously coat a deep baking pan with olive oil. Use more than you think you'll need. The olive oil is what gives focaccia its signature crispy, golden crust.
Transfer the dough into the prepared pan. If it sticks to the bowl, don't worry. Use a spatula or your hands to scrape every bit of dough into the pan.
Using the stretch and fold method, gently pull one side of the dough up and fold it toward the center. Rotate the pan and repeat on all four sides until the dough forms a loose ball or log shape.
Cover the pan with the same kitchen towel and let the dough rise for another 30 to 45 minutes.
Drizzle additional olive oil over the top of the dough. Gently stretch the dough toward the edges of the pan until it fills the corners. If it springs back, let it rest for a few minutes before trying again.
Using your fingertips, press deep dimples all over the surface of the dough.
Sprinkle with flaky sea salt, fresh rosemary, Italian seasoning, or your favorite toppings.
Bake at 425°F for 20 to 25 minutes, or until the top is golden brown and the edges are crisp.
Let the focaccia cool for a few minutes before slicing and serving. Enjoy warm with olive oil, butter, or alongside your favorite meal.