Line a rimmed baking sheet with aluminum foil. Set aside.
In a heavy medium skillet over high heat, heat until very hot. Meanwhile, rub 1 tablespoon olive oil all over the lamb. Season with salt and pepper generously. Place the lamb in the skillet and sear all sides until golden brown, about 3 minutes per side. Transfer to a large plate or baking sheet (not the prepared one). Let it rest for 30 minutes.
Preheat the oven to 450˚F (230˚C).
Tear the bread into cubes, including the crust. Put them in a food processor, process until they turn into fine crumbs. It’s ok that some are finer and some are bigger. Measure ½ cup of crumbs and put in a medium bowl. Add parmesan, rosemary and garlic. Mix well.
Have the lamb rack sitting bone side down. Rub 1 tablespoon of olive oil on the top side. Pat the bread crumbs on the top in an even layer. Carefully transfer the lamb to the prepared baking sheet.
Roast in the oven until 120˚F (for medium-rare) in the center of the meat, about 25 – 35 minutes. Check the crust occasionally. If it starts to get too brown, cover the crust with a piece of aluminum foil. Remove the lamb from oven. Cover loosely with aluminum foil and rest until the internal temperature reaches 125˚F, about 10 minutes. Carve the lamb rack into chops and serve immediately.