Savory Lamb Rib Chops with Rosemary Butter and Sweet Potatoes

Ingredients

• 8 lamb rib chops, about 4 ounces each, 1-inch thick
• 4 T fresh rosemary leaves, finely chopped, divided
• 1 T finely chopped garlic
• 1/2 t black pepper
• 4 T unsalted butter, at room temperature
• Salt and pepper
• 4 medium sweet potatoes, about 2 pounds total, peeled and cut into 1-1/2-inch chunks