
Preheat oven to 375°. Sprinkle lamb with steak seasoning. Heat oil in a large skillet over medium-high heat; brown lamb 2 minutes on each side. Brush with mustard.
In a small bowl, combine panko, thyme, mint, Worcestershire sauce and rosemary; press onto lamb. Transfer to a greased 15x10-in. baking pan. Bake, uncovered, until meat reaches desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°), 15-20 minutes.
In same skillet, saute mushrooms in olive oil and 2 tablespoons butter until tender, 3-5 minutes. Add garlic; cook 1 minute longer. Stir in wine. Bring to a boil; cook until liquid is reduced by half. Remove from the heat. Stir in the broth, honey, remaining butter and, if desired, chives.
Remove lamb from oven and loosely cover with foil. Let stand for 5 minutes before slicing. Serve with sauce.