Put the yeast and sugar in a large mixing bowl. Stir in 2 ½ cups of warm water, give it a gentle stir and then let it sit for 10 minutes.
Mix the flour and the sea salt together in a large mixing bowl and add it to the yeast mixture. Mix it up until you have a nice shaggy looking ball of dough.
Wipe out the bowl that had the flour in it and pour in a quarter cup of olive oil. Put your dough in the bowl, turn it around so it is all coated with the oil, and then cover the bowl with plastic wrap. Pop it in your fridge and let it sit overnight (you want at least 10 hours of rising time, and for the dough to be nice and big, about double in size).
Once the dough has risen, line a 13 x 9 inch rimmed baking pan with parchment and drizzle the parchment with 2 tablespoons of olive oil.
Take the dough out of the fridge and squish it with your hands a few times to flatten it out, and, and then transfer it to your baking pan. Smoosh it a little more until it is roughly a rectangle. Let it rise for another 2 to 3 hours (hey, nobody said this was going to be speedy!) until it is puffy and a little more risen.
Preheat your oven to 450. Now smoosh the dough to the edges of the baking sheet and then press your fingers into it until it is covered in little dents. Drizzle it with another tablespoon or two of olive oil and give it a generous sprinkle of sea salt and rosemary leaves.
Pop it in the oven and bake it up until it is golden and puffed, about 25 minutes.
Now, this last part is optional – kinda, because it is SO delicious. Melt up a quarter cup or so of your favorite butter (hello, Kerrygold!) and drizzle it over the top. And slice it up!
Notes
Flour: Use good old regular all purpose flour
Yeast: I use the instant yeast in the jar, but the regular yeast in the packet will work just as well.
Water: Make sure it is nice and warm but not HOT – yeast is an actual living thing, and we don’t want to damage it.