Grate the onion and squeeze out its juice.
Next, combine all the ingredients in a suitable bowl.
Mix and knead just a little.
Place plastic wrap over the lid of a jar. Place some patty mixture on the plastic wrap. After shaping the patty, set it aside..
Repeat the process until all the patty mixture is used.
Place small square-cut parchment papers on top of the patties and let them chill in the refrigerator for a while.
If you're planning to make and enjoy the hamburgers immediately, an hour of refrigeration is sufficient.
If you want to store them for later, arrange them on a tray over parchment papers and put them into the freezer.
Later, transfer them to storage containers and store them in the freezer.
You can take them out and cook whenever you're ready. Bon appΓ©tit!