Combine water, yeast, and sugar in the bowl of a standing mixer and let stand for 10 minutes*.
Add flour, salt, and olive oil and knead the dough in the mixer, using the dough hook, for about 5 minutes.
Turn the dough onto a floured surface and knead by hand for an additional minute. Form the dough into a round and place into an oiled bowl. Cover with wax paper and a towel and let rise for 1 to 1 1/2 hours.
Generously brush a rimmed baking sheet (approximately 12x18 inches) with olive oil.
Once risen, press dough into baking sheet, cover with wax paper and a towel, and let rise for an additional hour.
Pre-heat oven to 425 degrees.
Once risen a second time, remove the wax paper and towel, and make indentations all over the dough using your index finger.
Generously brush dough with olive oil, and sprinkle with sea salt and rosemary.
Bake for 18 to 22 minutes, until golden brown.