Add the warm water, packet of active dry yeast, and sugar to a small bowl. Mix and let sit in a warm area for about 15 minutes until it gets foamy and bubbly.
In a mixer bowl, add the flour, salt, 1/2 Cup of the olive oil, and the yeast mixture. Mix on low speed until blended. Remove from the mixer and knead on a lightly floured surface until everything is well blended. If the dough is too dry, you can add water 1 Tablespoon at a time until it becomes more moist and easier to knead.
Lightly coat the inside of the mixing bowl with oil, place the dough in it, and cover with plastic wrap. Let sit in a warm place for 1 hour.
Pour 1/4 Cup olive oil onto a rimmed baking sheet and spread the dough over it to cover the sheet.
Using your finger tips, push holes into the top of the dough, then brush the top with the remaining 1/4 C olive oil. Cover with plastic wrap and let sit another hour.
Preheat oven to 425°F. Bake the dough until starts turning a light brown on top and gets crisp on the bottom, about 15-20 minutes.
While the dough cooks, remove the rosemary leaves from the stems.
When the focaccia is done cooking, lightly brush it with olive oil and sprinkle on the rosemary and salt. You could also choose to add the salt and rosemary before baking.
** Nutritional information is an estimate and may vary.