Grate the zucchinis into a large bowl, then gently squeeze out excess moisture with your hands or a clean towel.
Heat olive oil in a wide skillet over medium heat until shimmering and fragrant.
Add the grated zucchini to the skillet and cook, stirring occasionally, until it shrinks and begins to turn lightly golden, about 8 minutes. This develops a sweet aroma and slightly crispy edges.
Push the zucchini to one side of the pan, then add chopped onion and cook until soft and fragrant, about 3 minutes. The onion should become translucent and smell sweet.
Add the minced garlic and cook for another minute until fragrant, being careful not to burn it.
Mix the zucchini, onion, and garlic together, then pour in the crushed tomatoes. Stir well to combine.
Bring the sauce to a gentle simmer and cook uncovered on low heat for about 20 minutes, stirring occasionally. The sauce will thicken and develop a rich aroma.
Taste and season with salt and pepper as needed, then stir in chopped fresh herbs for brightness.
Once the sauce has thickened to coat the back of a spoon and the zucchini is tender, remove from heat.
Serve hot over your favorite pasta, grains, or enjoy as a hearty vegetable main. Garnish with additional herbs if desired.
