In a large bowl, whisk together the flour and salt. Sprinkle the yeast over top (do not be tempted to whisk the yeast into the flour mixture as salt kills yeast; we’re keeping them “sort of” apart on purpose).

Add the water and stir with a spatula until the water is absorbed, any dry streaks are gone, and the mixture forms a tacky ball (more of a cohesive mass than a ball).

Using your hands, coat the top of the dough with a generous amount of olive oil (make sure it’s well coated so it doesn’t dry out and form a crust in the refrigerator).

Cover the bowl with plastic wrap and refrigerate for 18 to 24 hours (and up to 72 hours).

Coat a 9x13-inch baking pan with 2 tablespoons of the olive oil (or line with parchment paper and then add the oil; tip – coating the pan with cooking spray helps keep the parchment paper in place).

Remove the dough from the refrigerator and, using two forks, release the dough from two opposite sides of the bowl and pull the dough towards the center. Turn the bowl 1/4 turn and repeat. Do this 2 more times (the goal is to create a ball while gently deflating the dough).

Use a spatula to gently shape the dough into a rough ball. Transfer the dough to the prepared baking pan and turn to coat all sides with the oil.

Let rise, uncovered, in a dry, warm spot (like on top of the fridge or a preheating oven), until doubled in size, 1 1/2 hours to 4 hours (timing depends on your room temperature; mine took 2 hours sitting on top of my preheating oven). Your dough is ready when you can leave a visible indentation with your finger (if the dough springs back quickly, it’s not ready).

Preheat the oven to 425 degrees.

If you’re using rosemary or other ingredients, place them on top of the dough. Cover the top of the dough with the remaining 2 tablespoons of olive oil. Using oiled fingers, press straight down into the dough, reaching the bottom of the pan to create deep dimples. Sprinkle the top with salt, preferably coarse salt.

Bake for 20 to 25 minutes, until puffed up, golden brown on top, and the edges have just started to pull away from the sides of the pan.

Cool the focaccia, in the pan, on a wire rack for 5 minutes before slicing. Serve warm.