Something my mother used to make for me when I was still home.
In Slovakia hamburgers are made breaded, i.e., put into flour, then dipped into beaten eggs, then covered with breading (is that the right word?) and fried in oil.
Anyway, as a kid I really hated meat, so she would boil some Brussels sprouts, mush them up, form a burger, then bread it and fry. I loved it!
Alternately, sometimes she would do the same but use cauliflower instead. Either way, it was delicious.
If you are a vegetarian, or just want something different, give it a try.
My mother's name was Dela (short for Delfina), so please call them Dela's Burgers.