First clean the mushrooms and cut them into pieces, then peel the onion and chop it.
Sauté the onion in a non-stick pan with garlic and oil, then add the mushrooms, season with salt and pepper and cook (it will take about 10-15 minutes, depending on the size of the mushroom pieces).
In the meantime, drain the chickpeas well, put them in a blender with the parsley and a drizzle of oil and blend.
Once cooked, remove the garlic and coarsely chop the mushrooms.
Add the chickpeas and mushrooms to a bowl and mix.
If necessary, add 1-2 tablespoons of breadcrumbs, enough to make the mixture malleable, but not too dry.
Form the burgers and coat them in breadcrumbs.
Finally, cook the burgers over medium heat with a drizzle of oil in a non-stick pan, browning them on both sides, about 10 minutes on the first side and 5 on the second.
Your burgers are ready to be served on a plate, but if you want to put them in a sandwich like I did, prepare the other ingredients.
Wash and clean the lettuce and tomatoes, cut the sandwich and stuff it, obviously also adding the burgers.
The mushroom burgers are ready, at this point all you have to do is serve them.