2 pounds lean ground beef
1 package dry onion soup mix
3/4 cup milk
1/2 to 1 cup plain bread crumbs
1/3 cup ketchup, plus extra ketchup to spread on top
2 pounds baby red potatoes, cut in wedges and partially cooked
3 cups ready-to-eat baby-cut carrots
3 stalks diced celery
1 small onion sliced
Fresh parsley, if desired
Heat gas or charcoal grill. Cut 6 (18 x 10-inch) sheets of heavy-duty foil; spray with cooking spray. In medium bowl, mix beef, dry soup mix, egg, ketchup, milk and bread crumbs. Start with a 1/2 cup bread crumbs and add more if needed. Shape into 6 patties. Place 1 on each foil sheet; top each with about 1 tablespoon of the ketchup. Place some potatoes, sliced onion, celery and carrots around each.
Bring up 2 sides of foil so edges meet. Seal edges, making tight 1/2-inch fold; fold again, allowing space for heat circulation and expansion. Fold other sides to seal.
Place packets on grill. Cover grill; cook over medium heat 25 to 30 minutes, rotating packets 1/2 turn after 15 minutes, until vegetables are tender and meat thermometer inserted in center of loaves reads 160 degrees F. Serve with butter if desired and garnish with parsley.