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Just as the name describes this loaded vegetable Spaghetti Bake is packed with hearty, flavorful vegetables including onion, olives, eggplant, zucchini and mushrooms.
Feel free to add your family favorite vegetables or pre-cooked Italian sausage or ground meat if desired. Simply mix everything together and bake!
Loaded Vegetable Spaghetti Bake
For this simple casserole we set out to make a hearty, flavorful vegetarian meal without much effort. Eggplant, zucchini and mushrooms are sautéed until lightly charred locking in plenty of flavor and releasing most of the moisture.
Next the vegetables are mixed with Italian seasoning, marinara sauce, garlic, uncooked spaghetti (or your favorite pasta), chopped onions and olives. Pour water over the entire casserole, cover and bake!
While you can skip the sautéed vegetables to cut a little prep time, I guarantee it’s worth the extra 15 minutes of effort to bulk up on vegetables. If you’re looking for great flavors in a very filling vegetarian casserole, give this recipe a try. Your family won’t miss the meat!
Ingredients overview for vegetable Spaghetti Bake
- uncooked spaghetti noodles or your favorite pasta like rigatoni, ziti, penne or bow ties
- marinara or pasta sauce, homemade or store-bought
- Italian seasoning blend
- large sweet onion, chopped
- pitted kalamata olives, minced
- Parmesan cheese
- eggplant, peeled and chopped
- zucchini, cut into 1/2-inch pieces
- mushrooms, sliced
- olive oil
- garlic, minced
- crushed red pepper flakes (optional)
- salt and pepper
- shredded mozzarella cheese
- fresh basil leaves
How to make loaded vegetable Spaghetti Bake
1. Prep the pan and oven
- First, preheat oven to 375 degrees F. Lightly coat a deep 13×9-inch baking dish with vegetable cooking spray.
- Break the spaghetti noodles in half (to make it easier to stir) and layer in the prepared pan. Pour the marinara over the noodles. Sprinkle with Italian seasoning, diced onions, olives and Parmesan on top. Set aside.
2. Sauté vegetables
- In a large bowl toss the diced eggplant with salt. Layer a microwave safe plate with a few layers of paper towels or paper coffee filters. Lightly coat with vegetable cooking spray. Spread the eggplant in an even layer over the towels.
- Microwave, uncovered, until dry to the touch and slightly shriveled, about 10 minutes. Wipe out the large bowl then add the cooked eggplant back to the bowl along with the diced zucchini.
- Heat olive oil in a large nonstick skillet until shimmering. Add half the eggplant mixture. Season with salt and pepper and cook until vegetables are lightly browned. Add olive oil, garlic and crushed red pepper flakes and sauté until fragrant. Pour the sautéed vegetables to the baking dish with the spaghetti. Repeat with remaining eggplant and squash.
- In the now empty skillet add the remaining olive oil. Once hot add the mushrooms and cook undisturbed until dark on one side. Stir and continue cooking until the moisture is released and then evaporates, and the mushroom are well browned. Transfer to the casserole dish with the other vegetables.
3. Cover and bake
- Add 3 cups of water to the vegetable spaghetti mixture. Stir gently to combine. Cover with foil and bake for 30 minutes. Remove from the oven and carefully remove the foil. Stir then cover gain and continue baking for another 15 to 20 minutes.
- Remove the foil, top with mozzarella and bake uncovered for an additional 10 minutes or until the cheese is melted. Cool on a wire rack for 15 minutes before serving. Sprinkle with fresh basil leaves and serve.
Storing and reheating
Leftover vegetarian baked spaghetti is easily stored in an airtight container and refrigerated for up to 4 days.
To reheat, place the desired portion in a microwave safe dish and add about 1/4 cup of water. Cover and heat on 50% power for 3 to 5 minutes or until hot.
Shortcuts and variations
If you want to skip sautéing eggplant, zucchini and mushrooms simply bake with diced onions, olives and garlic. Add 3 tablespoons of olive oil with the water, cover and bake.
Here are a few more variations you might like:
- Stir in leftover shredded rotisserie chicken with the water.
- Add cooked and drained Italian sausage or ground beef before baking. You can also use a combination of the two.
- Add more cheese if desired.
- Use your favorite pasta like rigatoni, ziti, penne or bow ties
Loaded Vegetable Spaghetti Bake
- 1 pound spaghetti noodles
- 24 ounces marinara or pasta sauce homemade or store-bought (3 cups)
- 1 teaspoon Italian seasoning blend
- 1 large sweet onion diced
- ¼ cup pitted kalamata olives minced (10oz or 30g)
- ½ cup fresh shredded Parmesan cheese (1 ½ oz or 43g)
- 1 ½ pounds eggplant peeled and cut into 1/2-inch cubes (about 5 cups)
- 1 ½ pounds zucchini cut into 1/2-inch pieces (about 5 cups)
- 12 ounces mushrooms sliced
- 6 tablespoons olive oil divided
- 4 cloves garlic minced
- ¼ teaspoon crushed red pepper flakes (optional)
- salt and pepper
- 3 cups water
- 8 ounces shredded mozzarella cheese or more to taste
- 2 tablespoons chopped fresh basil leaves
- Preheat oven to 375°F.
- Lightly coat a deep 13 by 9-inch baking dish with vegetable cooking spray. Break the spaghetti noodles in half and layer in the prepared pan. Pour the marinara over the noodles. Sprinkle the Italian seasoning, diced onions, olives and Parmesan on top of the sauce. Set aside.
- In a large bowl toss the eggplant with 1 teaspoon salt. Line a microwave safe plate with a few layers of paper towels or paper coffee filters. Lightly coat with vegetable cooking spray. Spread the eggplant in an even layer over the paper towels. Wipe out the bowl and set aside.
- Microwave the eggplant, uncovered, until dry to the touch and slightly shriveled, about 10 minutes tossing halfway through cooking. Return the eggplant to the large bowl and add the zucchini.
- Heat 2 tablespoons olive oil in a large nonstick skillet over medium-high heat until shimmering. Add half the eggplant mixture. Season with 1/4 teaspoon salt and 1/4 teaspoon pepper. Cook stirring occasionally until the vegetables are lightly browned, about 8 minutes. Make an opening in the middle of the skillet and add 1/2 tablespoon oil, half the garlic and the red pepper flakes. Mash the garlic with a spatula and cook until fragrant, about 1 minute. Stir to combine the garlic and vegetables together. Transfer the mixture to the baking dish with the spaghetti.
- Repeat by adding 2 tablespoons olive oil and remaining squash and eggplant. Cook until browned then add another 1/2 tablespoon oil and the remaining garlic. Cook until fragrant then stir to combine. Transfer to the baking dish.
- In the now empty skillet add the remaining 1 tablespoon of olive oil. Once shimmering, add the sliced mushrooms and cook undisturbed until the mushrooms are very dark on one side. Stir and turn the mushrooms and continue cooking until the moisture is released, then evaporates, and the mushrooms are all well browned. Transfer to the casserole dish with the other vegetables.
- Add 3 cups of water to the vegetable spaghetti mixture. Stir gently to combine. Cover with foil and bake at 375°F for 30 minutes. Remove from the oven and stir to combine. Cover again and continue baking for another 15 to 20 minutes. Remove the foil, top with mozzarella and bake uncovered for an additional 10 minutes or until the cheese is melted.
- Cool on a wire rack for 15 minutes before serving. Sprinkle with fresh basil and serve.
- Refrigerate leftovers in an airtight container for up to 4 days.
- Add a few tablespoons of water to each individual serving and rewarm on 50% power in the microwave until hot.
More great baked pasta recipes:
Everybody loves this family friendly Baked Ziti Recipe loaded with ricotta, Italian sausage and marinara.