Can be prepared in 45 minutes or less, but requires additional unattended time.
Makes 2 servings.
1 cup fresh bread crumbs from french bread
Whisk mustard, garlic and chopped thyme in small bowl to blend. Sprinkle lamb with salt and pepper. Place lamb on baking sheet, rounded side up. Spread mustard mixture evenly over lamb. (Lamb can be prepared up to 6 hours ahead. Refrigerate uncovered.)
Preheat oven to 425°F. Stir bread crumbs and oil in heavy medium skillet over medium heat until crumbs begin to crisp, about 5 minutes. Cool slightly. Press crumbs onto mustard coating on lamb. Roast lamb until thermometer inserted into center registers 125°F for rare, about 25 minutes. Garnish with thyme sprigs, if desired, and serve.