Place oil into a large non-stick frying pan over medium-high and heat until hot.
Add finely chopped mushrooms and cook, stirring for 4-5 minutes or until pan juices have evaporated. Remove from heat, drain excess liquid and set aside 10 minutes.
Combine mushrooms, beef mince, finely chopped onion, salt and pepper, Worcestershire sauce and lightly beaten egg in a large mixing bowl. Mix well using your hands. Form mixture into patties (2 per person), place onto a tray, cover with plastic wrap and refrigerate for 20 minutes.
Heat a large non-stick frying pan on medium-high heat. Cook patties for 4-5 minutes on each side or until cooked to your liking.
Grill hamburger buns. Top bun bases with shredded lettuce, sliced tomato and two patties. Drizzle with your choice of sauce as desired.
Mushroom Growers of Australia, courtesy of Fresh Finesse.
To lower the glycemic index (GI) and to increase the fibre content always choose multigrain hamburger buns.