To make the focaccia: mix together flour, salt and yeast. Pour warm water over the top (no warmer than 90 degrees F) and mix using a wooden spoon until all the water is evenly mixed in and there are no dry spots. Cover with plastic wrap and let rise at room temperature for 6-8 hours. Usually I start this part before I go to bed so that the bread is ready to go the next morning.

Uncover the dough and mix in the chopped olives by folding them in. Drizzle olive oil in a 10" cast iron skillet or cake pan and press the dough into the pan, working to stretch it slightly so that it comes to the edges. This may take a few minutes. If you stretch the dough and find that it springs back, cover it and come back to it in 15 minutes so that the gluten has time to relax again. Once the dough has reached the edges, cover and let rise for 1 hour.

Preheat an oven to 500 degrees F. Use your fingertips to press the dough into the pan until it fills every corner, popping any large bubbles that appear. Drizzle with more olive oil and sprinkle with flaky sea salt. Transfer skillet to oven and bake until top is golden brown and bubbly and bottom appears golden brown and crisp when you lift it with a thin spatula, about 20-25 minutes. Once bread has finished baking, remove from the oven and let cool slightly before cutting and serving.

To make the dipping sauce, mix all ingredients together, cover and let sit for 30 minutes. Serve with warm bread.