Heat the olive oil in a large skillet over medium heat until it shimmers softly, filling your kitchen with a fragrant aroma.
Add the finely chopped onion to the skillet and sauté, stirring occasionally, until it becomes translucent and fragrant, about 5 minutes.
Stir in the minced garlic and cook for about 1 minute until it releases a smoky, pungent aroma, being careful not to burn it.
Next, add the grated or finely diced zucchini, stirring to combine. Cook until the zucchini releases its moisture and becomes tender, about 8 minutes, watching for a slight shimmer from the oil.
Pour in the crushed tomatoes and stir well, allowing the mixture to simmer gently. Season with salt, pepper, and a pinch of red pepper flakes for a subtle kick.
Reduce the heat to low and let the sauce simmer uncovered for about 20 minutes, stirring occasionally until it thickens and the flavors meld beautifully.
Taste the sauce and adjust the seasoning as needed, ensuring the zucchini is tender and the sauce is thick enough to coat a spoon.
Serve the zucchini bolognese over your favorite cooked pasta or spiralized vegetables, then sprinkle with Parmesan or nutritional yeast for a cheesy finish.