Peel the bananas, scrape the white internal part of the peels, then shred them with a fork then cut them so the peels don't get too long. Reserve.
In medium-low heat, add the butter and olive oil to a pan, when heated add the mirepoix, saute until golden brown, about 7 minutes. Add the garlic, saute for 40 seconds. Add the mushrooms, a pinch of salt then saute until the mushroom release all the water and turn brown, it will be about 6,7 minutes more, in medium-low heat.
Add the banana peels, the thyme, vegetable bouillon, black pepper, mushroom powder, dark soy sauce, liquid smoke, and saute for 1 minute, add the water, saute for 3 minutes. Then add the tomatoes and the dark chocolate and let it cook in low heat for 10 minutes.
Add the plant-based milk, turn off the heat and serve over spaghetti pasta.