Saute onion and pepper in oil. When they have softened, add the carrot cut into thick slices, the mushrooms cut into 4, the sliced zucchini and diced potatoes and peas. We mix a few times in them with a wooden spoon and then we put a cup of hot water on them, so that they don't stick.
Let them simmer, stirring occasionally. If needed, we would drop hot water when they dropped.
When they are half done, add the tomatoes, season with salt and pepper and put them in the preheated oven at 170ºC, cover them with a lid and let them boil for approx. 35-40 minutes, until softened and reduced. Towards the end, we can discover the pan and let them brown in the oven for another 10 minutes.
When they are ready, cut the marshmallow into small pieces and sprinkle it on top. It's crazy!