Heat the olive oil in a medium/large heavy saucepan or dutch oven over medium-low heat. Add onion, carrots and celery and saute until soft, stirring frequently, about five minutes.
Add mushrooms and garlic and cook until garlic is fragrant and mushrooms are softened, about one minute. Add red pepper flakes, basil and oregano and stir until combined. Add the meat to the pan by breaking it up into small, even clumps with your hands.
Continue to stir over medium-low heat until meat is browned and cooked through, about 10 minutes. Then add diced tomatoes. Add the plum tomatoes by squeezing them with your hands into the pot, breaking them down into small chunks.
Stir until combined, bring to a simmer, then reduce the heat to low, cover the pan and let simmer for 20 minutes.
While the sauce is simmering, make the zucchini noodles.
Instructions for the zucchini noodles:
Using a julienne peeler or mandolin slicer, cut the zucchini into thin, spaghetti-style strips. Rotate the zucchini, slicing until you get to the seedy, watery middle and then stop. Do not use the seedy, watery core of the zucchini. Instead save it for another purpose (maybe zucchini bread or stir fry).
Place the zucchini noodles in a microwave-safe glass dish, sprinkle with salt and stir to coat evenly. Cover the dish and microwave for 2 minutes. Stir the noodles and microwave again until desired tenderness. For our microwave this is another 2.5 minutes.
Place zucchini noodles in a bowl and top with meat sauce. Bam! Deliciousness.