Heat a dutch oven or large pot with a lid over medium-low heat. Add the vegetable oil.
Once the oil is hot, add the sliced onions and sauté them stirring occasionally until they soften slightly, about 2 minutes.
Add the chopped carrots and sauté them stirring occasionally until the carrots soften slightly, about 3 minutes.
Add 1 tablespoon of the minced garlic and sauté for another minute.
Add the shiitake mushrooms and sauté for 2 minutes, stirring occasionally. Add the royal trumpet mushrooms and sauté for 2 minutes, stirring occasionally. Add the beech mushrooms, separating them out into small chunks. Turn down the heat to low and continue sautéeing until all the vegetables soften, about 5 minutes. Stir occasionally.
Turn off the heat. Add 1 tablespoon of the curry powder and stir to coat all of the vegetables. Set the whole pot aside.