Chef Michael Romano's finger-licking lamb appetizer is served with a maple-roasted squash cube for a touch of sweetness.
In a nonreactive bowl, combine mustard, vinegar, garlic, salt, and pepper with 2 teaspoons water. Slowly whisk in olive oil until mixture is emulsified; stir in basil. Add lamb chops and toss to coat. Cover bowl and transfer to refrigerator; let marinate for 1 to 3 hours.
Preheat a grill pan over high heat. Remove excess marinade from lamb chops and place on grill. Cook, turning once, 4 to 5 minutes per side for medium rare.
Place one butternut squash cube on each of 24 plates. Arrange one lamb chop on each plate, resting the bone of the chop on the squash cube. Garnish plates with arugula and serve.