In a large nonstick skillet saute peppers and onion in a little bit of olive oil until soft and caramelized, about 10 to 15 minutes; season to taste with salt and pepper. Remove from pan, and set aside.
Heat 2 C of water and 2 tbsp of Lipton® Recipe Secrets® Onion Soup Mix until boiling; cook for 5 minutes and remove from heat.
Combine ground beef with 2 tbsp of soup mix, mayonnaise and Worcestershire sauce. Divide meat into 4 equal portions and form into patties. Brown patties in the same skillet used for the peppers and onions. Cook over medium-high heat until desired level of doneness and top with a slice of cheese.
For assembly: place burgers on toasted french bread and top with cooked peppers and onions. Serve with prepared onion soup for dipping.