Cut garlic into a crush and separate them into two parts.
Put 1 tbsp of oil, onions, a little bit salt and one clove of garlic into a wok with low heat. Fry for about 20 - 25 minutes until they turn brown and soft. Put them on the dish.
Put 1 tbsp of oil, mushrooms and the second clove of garlic in the same wok and fry them until heated.
Cut the mini burger into half and put one slice of cheese inside. Then put them into the oven for about 350 degrees celsius until the cheese melted.
Put one tomato slice, some onions and mushrooms into each of 12 mini burgers.
Serve.
Notes
The longer you fry the onions, the more caramelized it will become resulting in a sweeter taste