Combine yeast and water in a large bowl. Using a wooden spoon, add 1 cup of flour and then the salt, mix until combined. Stir in the rest of the flour until fully incorporated.
Add 1 cup of cheese, and rosemary to your taste ( I put in very little, I just wanted a hint of rosemary) and stir until fully incorporated. Cover with a damp towel, and store in a draft free area. Let stand for 1 hour. Do NOT punch the dough down. Lightly grease a cast iron skillet. Sprinkle the top of dough with flour and cover hands with flour. Take the dough and form into a round disk and place into skillet. Cover with damp towel and let stand for another 30 minutes. Preheat oven to 400 degrees.
Drizzle a little oil over the top of dough, slash the top of dough with a knife creating an x. Sprinkle with salt and rosemary leaves. Bake for 35 to 40 minutes until the top is golden brown.