Method
Step 1
Tip the burger ingredients into a large mixing bowl: steak mince, onion, parsley, eggs, salt and pepper. Mix until well combined (you can use your hands). Shape into burger patties. Heat a few glugs of olive oil in a large frying pan on medium to high heat. When the oil is hot, gently lay the burger patties in the pan and fry for about 6 to 8 minutes on each side until golden. Drain on paper towels and keep warm.
Step 2
Turn the grill on in the oven. Place the mushrooms on a baking tray. Remove the stems and drizzle with olive oil. Season with salt and pepper. Grill for about 5 minutes on each side until done.
Step 3
To serve, place the mushrooms on the plate and top each with a burger patty, spinach leaf and slice of tomato. Serve slices of avocado on the side with a dollop of mayonnaise.