Red onion cut into thin quarters or rings, cucumber cut into slices.
Add the apple, also cut into strips.
Drain the liquid from the canned mushrooms, if necessary, cut.
Add the avocado slices.
And sliced or hand-torn lettuce leaves.
For the dressing, mix all the ingredients well, salt to taste – I added 2 pinches, someone will need more. The salad can be served immediately or let stand for a few minutes in the cold, but not more than half an hour.