Sauté onion in 2 teaspoons olive oil until tender, about 4 minutes.
Prepare Honey Dijon mustard by combining the ingredients and refrigerating until ready to use.
Thoroughly combine all burger ingredients in a large mixing bowl, make into 4 burger style patties. In a large skillet, on medium heat add 1 tablespoon olive oil, add patties and cook until brown on both sides, about 10-12 minutes. Enjoy with your favorite bun or roll, spread on Honey Dijon Mustard if desired.
Suggested toppings: sautéed mushrooms, tomato, red onion, romaine lettuce and Honey Dijon Mustard.