Trim the fat cap off of the lamb unless you love fat and like very lamby-tasting lamb.
Cut the racks of lamb into two-bone chops. You should get four chops plus one little half-bone piece from each rack.
Make the seasoning paste by combining the capers, garlic, mustard, and olive oil in a mortar and pestle or small food processor bowl and processing until a semi-smooth paste forms.
Coat each chop in some of the paste and place bone-side down on a parchment-lined baking pan.
Insert your probe (or, better, the ChefAlarm's optional needle probe) into one of the chops (a smaller one, so as to not overcook the little ones). Set the high-temp alarm for 110°F (43°C) and cook the lamb. It should take about 12–15 minutes to get up to temp. When the high-temp alarm sounds, remove the chops from the oven and flip them so they are bone-side up. Set them on the counter to carry over and cool.
Move your oven rack to the top or second-from-top spot. Preheat your oven to broil on high.
Set your ChefAlarm's low-temp alarm for 110°F (43°C). When the low-temp alarm sounds, re-set your high-temp alarm to 120°F (49°C).
Put the lamb back in the oven and watch it closely. As the tops brown and sear, flip them over or to one side.
When the high-temp alarm sounds, verify the internal temperature with your Thermapen ONE. Remove the chops to the counter and allow them to rest for about 5 minutes.
Cut each chop in half between their bones.
Serve with the herb sauce to accompany!