Pour the olive oil in a large pot and fry the carrots for 3-4 minutes and then add the mushrooms and fry them until they get soft, then add the tomato paste, the warm water, the minced beef, some salt and pepper. Mix well and let the sauce boil.
Take another pot and prepare the water for the pasta and when it is ready pour the spaghetti in, along with some salt and let them boil.
When the sauce is ready, pour it in a big bowl and when the spaghetti is done add it to the bowl with the sauce and mix well, so that it gets evenly distributed. Serve the food when it is warm and add on it teh grated cheese.