Cut the portobello mushrooms in slices (as thick as you like, I just cut them in half), then peel and finely chop the onions and the garlic cloves. Peel the carrot and thinly cut (or use a special peeler) to cut thin long julienne strips.
Put a deep pot to the stove to heat up, add the mushrooms and season with salt and pepper. Fry for 2-3 minutes, then add the onions, the garlic, and the carrot thin strips and fry for 2 more minutes.
Season the meat with salt and pepper (to taste) then add to the pot. Mix very well and crush the meat lumps. Leave to simmer while constantly stirring until all the meat changed its color (~5 minutes).
Add the tomatoes passata sauce then boil for 5 more minutes. Cut the fresh basil leaves into thin slices and add to the sauce, mix well.
Boil the whole-wheat spaghetti pasta according to the package instructions (usually around 9 minutes, but may differ slightly). Drain the spaghetti.
Serve while hot :)