Cut open the avocado, scrape out the meat with a spoon and then drizzle with the juice of half a lime. Squeeze the avocado with a fork and mix with the mayonnaise. Add the finely grated onion. Press the garlic and mix in as well. Finely dice the tomatoes and add to the avocado mayonnaise. Chop the coriander (if you don`t like one, you can also use parsley) and mix in. Finally, season everything with pepper and salt (fleur de sel) to taste. If you like it a little more fiery, you can also add a little chilli if you like.
I like to make the avocado mayonnaise with homemade burgers or chicken wraps.