Preheat oven to 375 degrees Fahrenheit
Add yeast, sugar, water, flour, salt and rosemary to the bowl of a stand mixer or bread machine.
Mix until the dough is no longer sticky and starts to pull away from the sides of the bowl. Add flour a few tablespoons at a time as needed to achieve this consistency.
Knead in a stand mixer for 7-10 minutes, or let the bread machine run on the dough cycle.
Cover bowl with a clean kitchen towel and let dough rise in a warm place until double in size, about 1 hour.
Shape dough into a smooth ball. Add a drizzle of oil to a baking sheet and place the dough on the oil. Let rise for 15-20 minutes.
Sprinkle the top of the dough with more rosemary, if desired. Place the butter pat on top of the loaf.
Fill a shallow baking dish with water and place it on the bottom rack of your oven.
Bake the bread for about 30 minutes, or until the internal temperature reaches 190 degrees F. It should be a deep golden brown and sound hollow when tapped.