Mix the minced meat, chilli sauce, salt and pepper in a bowl and form four equal approx. 2 cm high burger patties. Use your thumb to press an approx. 2.5 cm wide indentation in the center so that the burgers become even and not bulge when grilling.
Grill the burgers medium over direct high heat with the lid closed for 8-10 minutes (for 1.5-2 minutes longer on each side). In the last few minutes, put the rolls on the grill and let them warm up briefly.
While the burgers are roasting on the grill, prepare the mayonnaise (it can also be prepared up to 6 hours in advance, then please cover it with cling film directly on the mayonnaise).
Put the grated onion in a colander, rinse briefly with cold water and drain well, this will make it milder and not so spicy. Put the avocado and mayonnaise in a bowl, mash with a fork and mix well. Mix in the onions, tomatoes, parsley, lemon juice and garlic. Salt generously.
Cover the rolls with the burgers and top with the avocado mayonnaise.
Tip: If you want, you can put a slice of cheese under the burger.