Coat a large nonstick skillet with cooking spray; place over medium-high heat until hot. Add cabbage, bell pepper, and onion; sauté 3 minutes. Add water, 1 tablespoon at a time, allowing each tablespoon to evaporate before adding the next; cook 5 minutes or until all liquid evaporates and vegetables are golden brown. Remove from heat; stir in oregano and rosemary. Let cool slightly.
Combine breadcrumbs and next 4 ingredients (breadcrumbs through egg white) in a medium bowl; stir well. Add cabbage mixture and beef; stir well. Divide mixture into 4 equal portions, shaping into 1/2-inch-thick patties.
Prepare grill. Place patties on grill rack coated with cooking spray; grill 5 minutes on each side or until done.
Spread 1 1/2 teaspoons ranch dressing over top half of each bun. Line bottom halves of buns with lettuce leaves; top each with a patty, tomato slice, onion slice, and top half of bun.