Remove the lamb from the refrigerator 30-40 minutes before baking to let it come to room temp. This will result in juicier, more evenly cooked meat.
Preheat the oven to 350°.Using a sharp knife, score the fat/top side of the lamb by making 10-12 shallow cuts into it then generously season the roast on all sides and ends with salt and pepper.
Warm a large skillet with 1/2 tablespoon of olive oil over medium high heat then carefully place the roast in the skillet. Sear all sides finishing with the fat side up.
In a small bowl blend 1 tablespoon of olive oil, the finely minced garlic, minced rosemary and thyme, Dijon mustard and the juice and zest from half of one lemon.
Spread the herb blend over the top of the roast pressing some into the slits.
Place the lamb in a roasting pan with a rack then roast uncovered 1 to 1 1/2 hours. Cook to your desired doneness beginning to check the temperature after roasting about an hour or so. I prefer medium so I remove it from the oven when the internal temp is about 135° to allow for carry-over cooking.
Medium rare: 130-135 degrees, Medium: 140-145 degrees, Well done: 150-155 degrees
Remove the roast from the oven and let it rest for 15 minutes before slicing.