Simple Vegetable Pasta Bake

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Easy and healthy comfort food for dinner tonight, this Simple Vegetable Pasta Bake is a long time vegetarian favorite in our house! It’s an easy way to eat lots of veggies because they’re loaded with flavor and surrounded in molten melty cheese. We love this pasta bake with either my Best Oven Roasted Broccoli or my Easiest Garlic Roasted Green Beans.

Simple Veggie Pasta Bake in a white baking dish with a red and white linen and wooden spoon.

Tender pasta tangled up with caramelized onions and spinach, sauced with tomatoes, and baked into a perfection of cheesy comfort! Even though I can’t wait for summer, I’m still reveling in comfort food while it’s still chilly. There’s nothing quite like all the yummy things baked together into deliciousness. And… when it involves molten cheese, you can always count me in!

I’ve added all sorts of things to this pasta, but in the end I went with my original recipe in it’s simplicity. That’s not to say you can’t go a little wild with this though, it’s great with roasted delicata or butternut squash, browned hot italian sausage, or any of the different herb suggestions as well. You can also easily change up the flavors by using a different pasta sauce as well.

A spoonful of Simple Veggie Pasta Bake being lifted out of the baking dish with strings of cheese coming down.

So let’s just jump in and talk about the ingredients for this Simple Vegetable Pasta Bake!

  • Onions – are caramelized first as the base of this pasta bake. It takes a few minutes, but caramelized onions add so much flavor. And you can prep the rest of the ingredients while they cook.
  • Mushrooms – also add to the flavor of the sauce along with being a fantastic way to add a ‘meaty’ texture to this vegetarian dish.
  • Rosemary – is my favorite fresh herb to use here, but thyme works as well. You can also use dried herbs instead. The ratio is 3:1 fresh herb to dried herb. So to replace the 1 tablespoon fresh rosemary, use 1 teaspoon dried herb of choice. My top pick would be Italian seasoning in place of the fresh herbs.
  • Tomato Sauce This recipe works with a 28-oz can fire roasted tomatoes blended into a sauce in the blender. Or you can also use your favorite 25-oz jar of pasta sauce. With the fire roasted tomatoes you will need to add sea salt to taste. And with the jarred pasta sauce, you can easily customize this recipe by changing the flavor of sauce you use. Tomato basil has been my favorite, by the spicier arrabiata is really good here as well as a vodka tomato sauce or roasted garlic.
  • Spinach – adds a bright pop of color and loads of greens to the dinner table. It simply melts right into the pasta bake and is an easy way to add another serving of veggies.
  • Pasta – I use gluten free 100% brown rice pasta, (Jovial is our favorite because the texture is incredible). You can use any shape you like, but I would steer clear of any of the super small shapes. Penne and farfalle are my go-to’s for this recipe.
  • Fresh Mozzarella – is added in the middle of the pasta bake and on the top for cheesy goodness. I recommend not subbing in regular mozzarella since it’s drier. Fresh mozzarella sheds it’s moisture as it bakes which adds a touch of creaminess but also contributes to the moisture level of the pasta bake. I haven’t tried this with regular mozzarella that you can grate, so I’m not sure if the pasta bake would be too dry.

Ok… now we’re ready to make this Simple Vegetable Pasta Bake step by step:

All the ingredients for the Simple Veggie Pasta Bake prepped on a wooden cutting board.

Step 1:

Prep the onions and get them caramelizing. They take at least 20 minutes to get that perfect golden browned flavor and you can prep everything else while they cook!

To prepare the onions, cut off both ends and peel the outer layer. Next lay each onion half flat side down on the cutting board – then cut across the rounded top to create 1/4″ half moon slices.

Caramelizing the onions for the the pasta.

Step 2:

Caramelize the onions in a skillet over medium heat. Cook until they’re golden browned and softened, about 20 minutes.

Tip: I highly recommend doubling the amount of onions called for in the recipe. Try them out in an omelet or with my In and Out Style Burger Lettuce Wraps.

Adding the mushrooms to the caramelized onions in a white skillet.

Step 3:

When the onions are done, add the chopped rosemary and mushrooms to the pan. Cook stirring frequently until the mushrooms are partially softened.

Tomato sauce added to the onion and mushroom mixture.

Steps 4 & 5:

In the meantime, cook the pasta until it is just softened but with a fair bit of bite left to it. This is about 4 minutes less than the usual cooking time, (it finishes cooking in the oven).

Next add the pasta sauce to the pan with the veggies, and bring it to a simmer.

The final step for the sauce of adding the spinach to the tomato sauce mixture.

Step 6 & 7:

Add the roughly chopped spinach to the pasta sauce mixture. Mix it in the best you can and remove it from the heat. Don’t worry about fully cooking the spinach, it will finish in the oven.

Toss the freshly cooked pasta together with the tomato sauce mixture and layer it into a deep dish baking dish.

Pasta mixed into the tomato sauce and placed in a baking dish and topped with fresh mozzarella.

Steps 8 & 9:

I like to add about 1/3 of the fresh mozzarella right into the pasta mixture – that way there’s cheesy pockets in the middle of the pasta bake! Then top the pasta bake with the remaining mozzarella.

Place the pasta dish in the oven and bake until the cheese is melted and browning, and the pasta bake is bubbling. Serve immediately!

Finished pasta bake in a white baking dish with a wooden spoon and a sprig of rosemary.

For more vegetarian dinner recipe options:

Straight down view of the Simple Veggie Pasta Bake in a white baking dish with a wooden serving spoon.

And if you’re looking for more pasta recipes:

Up close view of the pasta bake being scooped out with a wooden spoon.

Also for even more vegetarian recipe inspiration, you can head over to the recipe index for the whole lineup. I really hope you enjoy this simple and easy dinner! And if you do get a chance to make this, I hope you’ll leave me a comment/rating below. I always love hearing from you here!

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Finished pasta bake in a white baking dish with a wooden spoon and a sprig of rosemary.

Simple Vegetable Pasta Bake

  • Author: Kari
  • Total Time: 1 hour
  • Yield: 4 1x
  • Diet: Gluten Free



1/4 cup olive oil

1 large onion, 1 pound, halved and sliced into 1/4” slices

8 ounces crimini mushrooms, cleaned and sliced, about 10

1 tablespoon chopped fresh rosemary, or 1 teaspoon dried Italian seasoning

125 ounce jar pasta sauce, I used tomato basil, see notes

4 cups baby spinach, roughly chopped, 4 ounces

112 ounce box pasta, I used 100% brown rice penne

12 ounces fresh mozzarella, cut into 1/2” chunks


Preheat a large 12″ skillet over medium heat, and preheat the oven to 450ºF.

Add the olive oil and sliced onion to the preheated skillet. Sauté the onions until they caramelize, about 20 minutes. Don’t be tempted to turn up the heat, the onions won’t properly caramelize over high heat.

While the onions cook, prepare the rest of the ingredients. When the onions are done, add the mushrooms and rosemary to the pan and cook just until the mushrooms begin to soften. 

Meanwhile bring a pot of water to a boil and cook the pasta until it has softened but is firmer than you would usually cook it, about 4 minutes less than the cooking time listed on the box.

Add the pasta sauce to the veggies, and simmer 1-2 minutes. Then add the spinach, stir to combine, and remove it from the heat.

Drain the pasta and add it to the sauce mixture. Season to taste with salt and pepper.

Stir to combine and then add about 1/3 of the fresh mozzarella cubes. Mix thoroughly, then transfer the pasta into a deep dish 11″ x 7″ baking dish.

Top with the remaining mozzarella and bake for 20-25 minutes, or until the cheese begins to bubble and brown.

Serve immediately.


You can also use 1-28 ounce can fire roasted tomatoes blended into a sauce. You’ll need to simmer it for 5 minutes in the skillet with the onions and mushrooms and season to taste with salt.

  • Prep Time: 20 mins
  • Cook Time: 40 mins
  • Category: Dinner
  • Method: Baking
  • Cuisine: Italian

Keywords: Vegetarian Pasta Bake, Pasta Bake, Baked Pasta, Vegetable Pasta Bake, Easy Vegetable Pasta Bake

12 thoughts on “Simple Vegetable Pasta Bake”

    • I’m sorry it’s difficult for you to follow recipes in cups with pounds and ounces, but that’s what everything comes in here. You can however convert things with an online calculator if that would be helpful. My recipe format doesn’t allow for me to display a recipe in both Imperial and Metric.

  1. Have you ever made this a few hours ahead of time and put in the refrigerator until dinner then put it in the oven? I was thinking to prepare while kids at school then after activities just throw in the oven when we get home?

    • I haven’t tried making it ahead before, but it should work fine other than the baking time will be a bit longer coming from the refrigerator.

    • Thanks for letting me know about the mobile site! We’ve been working on some major updates so the site will run/work better, especially for phones! 🙂

  2. I love the simple elegance of this recipe, think I should add the butternut squash & mushrooms. My husband always *thinks* he has to have meat in every meal, but I think this recipe might just convince him otherwise! Looks delicious.

    • I hope you do add the butternut and mushrooms, it makes a great meatless meal (and my husband likes it so it’s already been husband tested)! 🙂


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