Cook about 3/4 to 1 cup of rice. Fluff, tip out of pot (or rice cooker) and let cool on counter.
Dice mushrooms and cook on a very high heat to ensure they don't boil themselves. Add shallots and garlic as well. Tip out of pan to let cool on counter.
Mash the canned or cooked black beans. I will mash mine with the back of a fork until about 80-85% of the way so there are still some visible beans.
Mix all ingredients thoroughly. Give it a squeeze of lemon or lime and a taste. Unlike meat burgers it is perfectly safe to try this mixture "raw"! Adjust seasoning, if needed.
Form into patties of your desired shape/thickness, but don't make them too thin or you risk them falling apart as they cook. Set aside in the fridge for a couple hours to set up and let the flavours mingle.
Cook in a pan or a barbecue over medium or so heat for about 5-7 minutes per side. Get a nice golden crunchy outside and hot center.