Dice the onion and red pepper. Mince the garlic. Peel and cut the carrot. Slice the mushrooms and celery.
In a large non-stick pot, heat the olive oil and add the onion, garlic, and carrot. Cook for 2-3 minutes and then add the red pepper and celery. Cook 2 minutes and add the ground beef. Cook until browned and add the mushrooms. Cook until the mushrooms have softened.
Add the tomato cans, bouillon, spices and tomato paste. Mix to combine and simmer for an hour on low heat, covered. Mix the sauce from time to time to prevent sticking to the bottom.
After simmering for an hour, uncover and simmer for an additional 10 minutes to make the extra liquid evaporate. Turn off heat and the sauce is ready to serve.
Using a spiralizer, spiralize the zucchinis with the blade of your choice. I like to warm up the zucchini in a non-stick frying pan with no oil, just for 30sec-1min until they're warm and top with the sauce.