Peel the onions and cut them into small cubes. Peel the carrots and grate on a coarse grater.
Wipe the mushrooms with a dry cloth or paper towel. Remove the skin from the caps, and refresh the cut on the stem of each mushroom. Cut the mushrooms into slices.
Heat a skillet with vegetable oil and add chopped onions and carrots. While stirring, fry the vegetables over medium heat for 3-4 minutes, until soft.
Add the chopped mushrooms and fry for another 5-7 minutes, until the juice evaporates.
Add canned beans, 100 ml water, black pepper, and some salt to the pan (note that the beans may already be salted). Stir and cook covered over low heat for 10 minutes.