All of the flavors that you love from a classic bowl of French onion soup are transformed into a hearty casserole! This easy French onion pasta includes sweet caramelized onions, sautéed mushrooms, fresh spinach, garlic, herbs, and gooey melted Gruyere cheese.
Table of Contents
If you’re looking for even more French onion recipes, be sure to try this classic French onion soup, a French onion chicken casserole, and this shortcut dump-and-bake French onion chicken, too!
Why You’ll Love this French Onion Soup Pasta
- Complex Flavor. Bowls of French onion soup are typically topped with a slice or two of crusty bread and served au gratin — sprinkled with grated cheese and browned on top. The soup tastes slightly sweet, thanks to the caramelized onions, and savory — thanks to the herbs, broth, and garlic. Here, we’ve accomplished the same flavorful combination by substituting pasta for the bread, and browning cheese on top of the dish. Caramelized onions and sautéed mushrooms create a rich, flavorful base to the casserole, while herbs, Worcestershire sauce, and vinegar all add depth.
- Affordable. The pasta bake only requires simple ingredients that are easy to find in just about any store. You don’t have to purchase meat, so you have a budget-friendly dinner that’s still hearty and satisfying.
- Cozy. When you want a warm, comforting meal but a bowl of soup just won’t cut it, this pasta casserole is the way to go!
Ingredients
This is just a quick overview of the ingredients that you’ll need for a pan of French onion pasta. As always, specific measurements and step-by-step instructions are included in the printable recipe box at the bottom of the post.
- Butter: I prefer salted butter here, which you’ll use to caramelize the onions and to combine with the flour to create a roux.
- Onions: Vidalia onions are great since they’re so naturally sweet. That said, just about any onion will work, so use a variety that you like or that’s readily available.
- Mushrooms: add flavor and texture to the casserole.
- Garlic: for savory flavor.
- All-purpose flour: thickens the sauce.
- Thyme and bay leaf: for earthy, savory flavor.
- Beef broth or beef stock: the liquid base of the sauce. You can sub with vegetable broth for a vegetarian option, but it will have a different flavor.
- Worcestershire sauce: for salty umami flavor. Sub with soy sauce for a vegetarian option.
- Balsamic vinegar: an acidic note that brightens up the sauce. Sherry or sherry vinegar also work well.
- Kosher salt and ground black pepper: enhance the flavors of the other ingredients.
- Pasta: I like rigatoni in a pasta bake, but you can sub with penne or just about any other short pasta shape that you prefer.
- Fresh baby spinach: for color, texture, and added nutrition.
- Cheese: a traditional French onion soup recipe typically calls for Comté (or Gruyère de Comté), but you can also use Swiss Gruyère, Emmentaler, or Fontina cheeses. I tend to use a regular block of Swiss cheese, provolone cheese, mozzarella cheese, or even Gouda cheese, since that’s what’s readily available in my little grocery store. A sprinkling of Parmesan cheese is also delicious!
The Best Casserole Dish to Use
We rounded up the best casserole dishes you can buy, including 2 that I personally own and love! While I use different-sized casserole dishes for different meals, the Staub Ceramic Rectangular Baking Dish earned the top spot. You can buy it on Amazon for $78.64 or at Target for $79.95. That said, I also love the beautiful, Scandinavian style of the Dansk Kobenstyle Baker shown here, available for $135.
How to Make French Onion Pasta
This easy French onion pasta includes all of the flavors that you love from a bowl of French onion soup — and puts them into a hearty casserole! You’ll find detailed directions in the recipe card below, but here’s the quick version:
- Caramelize the onions, and then sauté the mushrooms and garlic.
- Finish the sauce with flour, seasoning, broth, Worcestershire sauce, and balsamic vinegar.
- Simmer until the sauce thickens slightly.
- Stir in the cooked pasta and the fresh spinach.
- Transfer to a baking dish and top with shredded cheese.
- Cover and bake for about 20 minutes.
- Remove the cover and place the dish under the broiler to brown the cheese on top.
Serving Suggestions
Here are some sides that go well with French onion pasta:
- Crusty Baguette, No-Knead Dutch Oven Bread, or No-knead Skillet Focaccia
- Cranberry Muffins or Apple Muffins
- Pumpkin Bread or Pumpkin Muffins
- Green Salad with Red Wine Vinaigrette, Mixed Greens with Dijon Vinaigrette, Caesar Salad, or our favorite House Salad with Candied Pecans
- Southern Fried Apples, Baked Apple Slices, or Applesauce
- Roasted Asparagus, Bacon Wrapped Asparagus, or Sauteed Asparagus
- Amish Green Beans with Brown Butter or Southern-Style Green Beans
- Parmesan Roasted Cauliflower or Roasted Broccoli
- Oven-Roasted Brussels Sprouts with Bacon or Roasted Root Vegetables
- Brown Sugar Glazed Carrots
- Roasted Cabbage, Braised Red Cabbage with Apples and Bacon, or Fried Cabbage with Apples and Onion
- Cranberry Sauce
Preparation and Storage Tips
- Make Ahead: Assemble the casserole up to 24 hours in advance. Cover with plastic wrap or aluminum foil and store in the fridge until ready to bake. When ready to bake, allow the dish to sit on the counter and come to room temperature for at least 30-60 minutes before placing it in the oven. If the dish is still cold when it goes into the oven, you may need to extend the baking time.
- Storage: Leftovers will keep in an airtight container in the fridge for 3-4 days, or in the freezer for up to 3 months. It’s important to note, however, that the texture of the pasta will not be as good when it thaws. Frozen and thawed noodles tend to have a gummy, mushy texture — definitely not ideal.
- How to Reheat: Cover and reheat leftovers in a 350°F oven for 20-25 minutes, or until warmed through. You can also reheat individual portions in a microwave for 1-2 minutes on high power.
Recipe Variations
- For a vegetarian French onion pasta bake, swap out the beef broth for vegetable broth and use soy sauce instead of Worcestershire sauce. The flavor will be slightly different, but it will still work well.
- A traditional French onion soup recipe typically calls for Comté (or Gruyère de Comté), but you can also use Swiss Gruyère, Emmentaler, or Fontina cheeses. I tend to use a regular block of Swiss cheese, provolone cheese, mozzarella cheese, or even Gouda cheese, since that’s what’s readily available in my little grocery store. A sprinkling of Parmesan cheese is also delicious!
- Add a splash of dry white wine or red wine to the sauce for even more flavor. For a slightly creamy sauce, add a little bit of heavy cream (to taste).
- For an even heartier, more filling pasta dish, add some extra protein with shredded rotisserie chicken, diced ham, or a can of drained, rinsed white beans or chickpeas. Bacon or sausage would also be tasty in this casserole.
- Chicken broth or chicken stock will work fine as a substitute for the beef broth.
- Instead of the balsamic vinegar, try adding a splash of dry sherry.
- In lieu of Vidalia onions, you can use yellow onions for a less sweet taste, or red onions for a bolder, zestier flavor.
- Any short pasta shape will work. For instance, replace the rigatoni with rotini, farfalle, penne, or ziti.
Tips for the Best French Onion Pasta Recipe
- Stir the onions regularly and add water to the pan as needed to ensure that the onions don’t burn. If they start to get too dark too quickly, just lower the temperature and cook them over medium-low or low heat.
- Boil the pasta just until it’s barely al dente (just about tender, but still with a firm bite). The rigatoni will continue to cook in the oven, and you don’t want it to come out mushy, gummy, and overdone.
- Bake the casserole covered so that it stays moist and doesn’t dry out. Then, for a crispy top, place the dish under the broiler for a minute or two before serving.
- Keep a close eye on the dish while it’s under the broiler, since the cheese can burn quickly.
- Garnish each serving with fresh herbs for a bright, colorful touch. Good options include fresh thyme leaves, parsley, rosemary, or chives.
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Did you make this recipe?
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French Onion Pasta Bake
Prep: 15 minutes
Cook: 1 hour 10 minutes
Total: 1 hour 25 minutes
A cozy, flavorful French onion pasta bake includes sweet caramelized onions, sauteed mushrooms, fresh spinach, and plenty of cheese!
Ingredients
- ¼ cup (half of a stick) salted butter
- 1 ½ lbs. Vidalia onions (about 1-2 large onions), peeled and sliced
- 8 ounces sliced fresh mushrooms
- 1 large clove garlic, peeled and minced (about 1 teaspoon)
- ¼ cup all-purpose flour
- 1 teaspoon minced fresh thyme (or ¼ teaspoon dried thyme)
- 2 ½ cups beef broth
- 1 tablespoon Worcestershire sauce
- 1 bay leaf
- 1 tablespoon balsamic vinegar
- Kosher salt and ground black pepper, to taste
- 1 (16 ounce) package rigatoni or penne pasta, cooked in a large pot of salted water according to package directions for al dente
- 2 cups coarsely chopped baby spinach
- 6 ounces (about 1 ½ cups) shredded Swiss cheese, Gruyere cheese, or mozzarella cheese
- Optional garnish: chopped fresh parsley or thyme
- Optional, for serving: sliced baguette
Instructions
- Preheat oven to 375°F. Grease a 9 x 13-inch baking dish with nonstick spray; set aside.
- Melt the butter in a large Dutch oven over medium heat. Add the onions and saute for 20 minutes, stirring frequently. Add the mushrooms and garlic; saute until mushrooms are tender, about 5-7 more minutes.
- Sprinkle in the flour and cook, stirring constantly, for 2 minutes. Add the thyme and about half of the beef broth. Deglaze the pan, stirring to loosen the cooked pieces on the bottom. Whisking constantly, add the remaining beef broth, Worcestershire sauce, and bay leaf. Increase the heat to medium-high and bring to a boil. Reduce the heat to low and simmer for 4-5 minutes, until the sauce thickens slightly. Stir in the balsamic vinegar and season with salt and pepper to taste. Discard bay leaf.
- Stir in the cooked pasta and the spinach. Transfer to the prepared baking dish. Top with shredded cheese. Cover with foil.
- Bake covered for about 20 minutes, until the filling is hot and bubbly. Remove the cover, and place the pan under the broiler for about 1 minute, or until the cheese is browned and crisp on top. Garnish with fresh herbs, if desired.
Notes
- Stir the onions regularly and add water to the pan as needed to ensure that the onions don’t burn. If they start to get too dark too quickly, just lower the temperature and cook them over medium-low or low heat.
- Boil the pasta just until it’s barely al dente (just about tender, but still with a firm bite). The rigatoni will continue to cook in the oven, and you don’t want it to come out mushy, gummy, and overdone.
- Bake the casserole covered so that it stays moist and doesn’t dry out. Then, for a crispy top, place the dish under the broiler for a minute or two before serving.
- Keep a close eye on the dish while it’s under the broiler, since the cheese can burn quickly.
- Garnish each serving with fresh herbs for a bright, colorful touch. Good options include fresh thyme leaves, parsley, rosemary, or chives.
Nutrition
Serving: 1/8 of the pastaCalories: 414kcalCarbohydrates: 55gProtein: 17gFat: 14gSaturated Fat: 8gPolyunsaturated Fat: 1gMonounsaturated Fat: 4gTrans Fat: 0.2gCholesterol: 39mgSodium: 519mgPotassium: 465mgFiber: 4gSugar: 6gVitamin A: 1085IUVitamin C: 9mgCalcium: 264mgIron: 2mg
Thank you so much for your recipes!
I especially love all the tips you give as I enjoy tweaking to our preferences or to what’s available!
We’re so glad you find them helpful, Colleen! We hope you continue to enjoy the recipes.