Step 1

In a large mixing bowl, add the bread flour and kosher salt into the bowl (see note #3 on weighing ingredients)

Step 2

In a heat proof measuring cup, microwave the water until it reaches 110F-115F temperature. The timing will depend on how cold your water is, use a food thermometer to check. Add the active dry yeast to the water and whisk until it dissolves and give it 5 minutes, so it begins to bubble. (see note #2 if using instant yeast). Add the water/yeast into the bowl with the flour. Using your hands or a rubber spatula, mix until there is no more dry flour. Cover tightly with plastic wrap and let rise overnight (minimum 8 hours, max 24 hours) (see note #4).

Step 3

After the dough has risen overnight, remove the plastic wrap. Take a rubber spatula and tuck the edges of the dough into the center of the dough, creating a ball. In a cast iron skillet, add 3 tbsp olive oil, then place the ball of dough into the cast iron seam side down. Allow the dough to sit in the cast iron for one hour.

Step 4

Preheat oven to 450 degrees F. After the dough has sat in the cast iron for one hour, using the palm of your hand, flatten the dough into the skillet spreading it to meet all sides of the skillet. Using your finger tips, dimple the dough by pressing all the way down to the bottom of the skillet. Brush/spread 3 tbsp olive oil onto the dough, allowing the oil to go into the dimples. Sprinkle flakey sea salt and fresh rosemary over the top.

Step 5

Bake the focaccia for about 20-25 minutes (turning skillet halfway through so it bakes evenly) until the top is golden brown. Remove the skillet from the oven using mitts. With a rubber spatula, gently lift the bread and check underneath to make sure it's fully cooked. Allow to rest for 15 minutes before cutting. Serve with a dish of olive oil for dipping, best enjoyed the day of (see note #5).