Roasted Zucchini Casserole

Step 1
Preheat the oven to 400 degrees F (200 degrees C).

Step 2
Toss zucchini and onions in a large bowl with olive oil until evenly coated. Spread vegetables into a large baking dish.

Step 3
Roast in the preheated oven until golden, about 30 minutes. Remove from the oven and season with salt and pepper. Reduce the oven temperature to 350 degrees F (175 degrees C).

Step 4
When the vegetables are almost finished roasting, bring a large pot of lightly salted water to a boil. Add penne and cook, stirring occasionally, until tender yet firm to the bite, about 11 minutes; drain.

Step 5
Lightly grease a 9×13-inch baking dish.

Step 6
Heat marinara sauce in a saucepan over medium heat until hot. Spread hot sauce into the prepared baking dish. Top with cooked penne, followed by roasted zucchini and onions. Sprinkle with Parmesan cheese.

Step 7
Bake in the preheated oven until sauce is bubbly, 35 to 40 minutes. Remove from the oven and let rest for 5 minutes before serving.