Preheat oven to 425°F. Season lamb all over with salt and pepper.

Heat oil in a 12-inch heavy skillet over moderate heat until hot but not smoking.

Brown lamb on both sides, about 6 minutes total. (Adjust heat accordingly so oil does not smoke and splatter.) Reserve the skillet to prepare the sauce.

Transfer lamb to a roasting pan and roast until thermometer inserted into center of meat registers 125°F for medium rare or 130°F for medium, 12 to 15 minutes. Let stand, loosely covered with foil, 10 minutes.

Meanwhile, make the sauce. After transferring the browned lamb to the roasting pan, pour off all but 1 tablespoon fat from the skillet.

Place the skillet over medium heat and add the shallots.

Cook until fragrant, stirring often, 2 to 3 minutes.

Add wine and lavender, increase the heat, and simmer until reduced by half, about 5 minutes.

Stir in sugar, blueberries and balsamic vinegar and simmer 2 minutes.

Add butter and swirl to incorporate it into the sauce.

Taste and adjust seasoning with salt and pepper. (If a smooth-textured sauce is desired, it can be cooled slightly and then puréed and strained.) Slice lamb into chops and serve with the sauce.