Step 1

For dressing, in a medium bowl combine oil, vinegar, green onion, marjoram, thyme, salt, and pepper.

Step 2

Place lamb chops in a shallow dish. Spoon about 1/4 cup of the dressing over lamb. Turn chops to coat with dressing. Cover dish and marinate in the refrigerator for at least 1 hour or up to 2 hours. Cover and set aside the remaining dressing.

Step 3

Meanwhile, cut each head of the radicchio into six wedges, cutting through the core; brush lightly with some of the remaining dressing. Thread tomatoes onto four skewers.* Thread radicchio wedges onto additional skewers, leaving 1/4 inch between pieces.

Step 4

For a charcoal or gas grill, grill chops on rack of a covered grill directly over medium heat to desired doneness, turning once halfway through grilling time. Allow 12 to 14 minutes for medium rare (145°F) or 15 to 17 minutes for medium (160°F). Add radicchio and tomatoes to grill. Grill for 2 to 3 minutes or until radicchio is slightly wilted and tomatoes are beginning to blister, turning once halfway through grilling time.

Step 5

Divide greens among four dinner plates. Remove radicchio and tomatoes from skewers. Arrange lamb chops, radicchio, and tomatoes on greens. Drizzle with the remaining dressing; top with radishes.