Directions :

1. To roast the zucchini:
2. Preheat oven to 450 degrees. Prepare two rimmed baking sheets with parchment paper for easy clean-up.
3. In a large bowl, add zucchini strips, extra-virgin olive oil, and season with salt and freshly ground black pepper (I like ½ teaspoon salt and ¼ teaspoon pepper). Toss to combine.
4. Arrange zucchini slices on prepared baking sheets in a single layer. Bake until zucchini is light golden brown and fork-tender, about 12 to 15 minutes. Drain on paper towels and reduce oven temperature to 375 degrees.
5. To make the sauce:
6. Meanwhile, in a medium saucepan over medium-high heat, add 1 tablespoon olive oil and heat until shimmering. Add minced garlic and stir until fragrant, about 30 seconds. Add crushed tomatoes (be careful; they may splatter when they hit the hot oil, so keep the lid handy), basil, oregano, and red pepper flakes (if using). Bring the sauce to boil over medium-high heat.
7. Reduce heat to medium-low, cover, and simmer until the flavors have blended, about 10 to 15 minutes longer. Season to taste with salt and pepper (I like ½ teaspoon salt and ¼ teaspoon pepper) and keep warm over medium-low heat.
8. To assemble and bake the casserole:
9. Spread ¼ cup tomato sauce over the bottom of a 2-quart casserole dish. Arrange one-third of the zucchini in an even layer over the tomato sauce. Spoon one-third of the remaining tomato sauce over zucchini.
10. Sprinkle ¼ cup Parmesan cheese over layer, followed by ¼ cup mozzarella. Repeat layers with remaining 2/3 zucchini slices, tomato sauce, and cheeses.
11. Bake until bubbling and cheese is browned and bubbling, about 30 to 35 minutes. Remove from oven and allow to rest 5 minutes before serving. Garnish with fresh parsley if desired.