Add olive oil to a skillet on medium heat, when hot, add the shredded mushroom and the soy sauce. Stir and let it brown.
Add olive oil to a thick pot, on medium heat, when hot add the onions, stir until golden brown.
Add the tomato pure, stir for 3 minutes, add the red bell peppers, sauté them for 3 minutes.
Add the remainder of the ingredients except the parsley. Turn the heat to medium low and let it cook for approximately 20 minutes. This time will vary according to the cassava you're using. The stew is ready when the cassava is cooked through. We are looking for a soft but firm cassava. If you cook it too long it will disintegrate and your stew will be really thick.
You may need to add some more water along the cooking.
When the stew is ready, turn off the heat and add fresh parsley for garnishing.