Sear the lamb, fat side down, until golden brown, then place the entire pan into the oven and roast for 20 to 25 minutes or until the internal temperature reaches 125 degrees F which will be a perfect medium-rare. To get the perfect temperature, a digital meat thermometer is super helpful.
This recipe works for both frenched and unfrenched racks of lamb. I often choose not to get the lamb frenched since it's not necessary and often costs more money, but many find it to appear more fancy and impressive when frenched. The choice is yours!