Preheat oven to 425°F and line a baking sheet with parchment paper. Oil a 9×13-inch baking dish.
Place mushrooms, red pepper, zucchini, and onion on the baking sheet. Drizzle with olive oil, season with salt and pepper, and roast for 20–25 minutes until tender.
Reduce oven temperature to 400°F.
Cook lasagna noodles until al dente, drain, and toss with olive oil to prevent sticking.
In a large bowl, mix ricotta, garlic, lemon zest, salt, and pepper.
Spread 1 cup marinara in the prepared dish. Add a layer of noodles, half the ricotta, half the spinach, half the vegetables, and ⅔ cup sauce.
Repeat layers, finishing with noodles, sauce, mozzarella, and pecorino.
Bake uncovered for 30 minutes until cheese is golden and bubbling.
Rest for 20 minutes before slicing. Garnish with basil or parsley.
