Combine yeast, sugar, and warm water in the bowl of a stand mixer fitted with a dough hook. Let the yeast proof for 5 minutes, until foamy and fragrant.
In a medium bowl, combine flour, salt, both kinds of rosemary, and roasted garlic. Add flour to mixing bowl in quarters, mixing with a dough hook between each addition. Continue to mix until all flour is incorporated and dough begins to pull away from the sides of the bowl.
Remove the bowl from the mixer and sprinkle dough with flour. Turn over the ball of dough and coat with flour on all sides. Cover the bowl with a tea towel and let it rise on the counter for about 1 hour, until the dough has doubled in size.
Then, gently pour the dough out of the bowl and onto a floured cutting board and sprinkle a bit of flour across the top. Shape it into a round loaf by pulling the corners in like an envelope.
Flour a proofing basketor a small mixing bowl and place your loaf into it seam-side down. Again, cover with a tea towel and let rise another 30 minutes.
While bread proofs, place an empty Dutch oven (with the lid on) in the oven and preheat to 460 degrees F.
When the oven is hot and bread is proofed, tip the bread dough gently out of the proofing basket back onto your cutting board, and carefully place it – seam side up into the dutch oven. Put the Dutch oven lid back on the pot and place in the oven. Be careful, the Dutch oven and knob will be very hot!
Cook bread for 30 minutes with the lid on, then remove the lid and cook for 15 minutes more, until the bread has a crunchy brown crust.
When the bread is done, remove dutch oven and use a wooden spoon to lift the bread onto a cooling rack. Cool for at least 20 minutes before cutting.
Remember the Dutch oven and lid will be VERY hot. Be careful!