Caramelized Onion Pasta Bake

This caramelized onion pasta bake is exactly what I want whenever I’m craving comfort food. The onions roast slowly in the oven with garlic and sun-dried tomatoes until they turn soft, sweet and jammy. Then they’re mixed with spinach, cream, pasta, and plenty of mozzarella before getting baked again until bubbly and golden on top.

Looking for more cozy dinners? Browse my Comfort Food Recipes.

INGREDIENTS YOU’LL NEED

• Yellow onions: The star of this caramelized onion pasta! Slow-roasted until sweet and soft.
• Garlic: Roasted whole, then squeezed into the onions for a mellow, sweet flavor.
• Sun-dried tomatoes: Give the bake tangy richness and balance the sweetness of the onions.
• Olive oil: Helps the onions caramelize beautifully in the oven.
• Lemon juice: Brightens up the creamy sauce so it doesn’t feel too heavy.
• Baby spinach: Wilts into the pasta bake for color and extra freshness.
• Parsley: Stirred into the sauce and sprinkled on top for a fresh finish.
• Heavy cream (or half-half): Makes the caramelized onion pasta bake rich and luscious.
• Short pasta: Penne, rigatoni or fusilli… anything that holds onto the sauce works well.
• Reserved pasta water: Helps loosen the sauce and coat the pasta evenly.
• Mozzarella cheese: Melts on top for that golden, bubbly finish.

HOW TO MAKE CARAMELIZED ONION PASTA BAKE

Please note: This is just an overview – the full ingredients and directions are in the recipe card at the bottom of this post.

Step 1: Roast the onions

Preheat your oven to 375°F (190°C). In a large baking dish, combine the sliced onions, whole head of garlic (cut side up), sun-dried tomatoes, Italian seasoning, chili flakes, olive oil, salt, and pepper. Toss everything well, cover tightly with foil, and roast for about 1 hour, until the onions are soft, jammy, and caramelized.

Step 2: Cook the pasta

While the onions roast, bring a large pot of salted water to a boil. Cook the pasta until al dente, then drain. Don’t forget to save a little of that starchy pasta water for later.

Step 3: Build the sauce

Remove the baking dish from the oven. Squeeze the roasted garlic cloves out of their skins and mash them into the onions. Add lemon juice, spinach, parsley, and cream, stirring until the spinach wilts and everything is creamy and fragrant.

Step 4: Mix with pasta

Add the cooked pasta to the baking dish and toss everything together, adding a splash of pasta water to help the sauce cling to the pasta.

Step 5: Top & bake again

Scatter mozzarella over the top and bake uncovered for 10–15 minutes, until bubbly and golden. For an extra crispy top, broil for 1–2 minutes at the end.

Step 6: Rest & serve

Let the caramelized onion pasta bake rest for a few minutes before serving. Garnish with more parsley and enjoy warm.

NOTES FROM MY KITCHEN

You don’t need to hover over this one. The onions and garlic roast slowly, covered and the oven does all the heavy lifting. The trick is letting them get soft, jammy and caramelized before you build the rest of the sauce.

I roast the garlic whole with the top trimmed off, just like you would for roasted garlic soup. It turns soft and mellow and can be squeezed right into the onion mixture. If you’ve never done this before, you’re in for a treat.

I like using sun-dried tomatoes in oil. They bring an extra layer of richness and a little bit of chew. If yours are packed dry, soak them in hot water for 10 minutes first.

You can use any short pasta here, like penne, rigatoni, fusilli, whatever you’ve got. I usually make this when I have an open bag of something half-full in the pantry.

The cream adds a lovely richness, but if you want to keep it a bit lighter, half-half works too. Just don’t skip the lemon, it balances the sweetness of the onions and brightens everything up.

And finally: don’t skip the mozzarella. This is a pasta bake after all. That golden, bubbling top is the whole point and it ties everything together.

Caramelized Onion Pasta Bake

Recipe by Magda | Good Food Discoveries

5.0 from 3 votes

This caramelized onion pasta bake is exactly what I want whenever I’m craving comfort food. The onions roast slowly in the oven with garlic and sun-dried tomatoes until they turn soft, sweet and jammy. Then they’re mixed with spinach, cream, pasta, and plenty of mozzarella before getting baked again until bubbly and golden on top.

Course: DinnerCuisine: AmericanDifficulty: Easy

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Servings

4

servings

Prep time

15

minutes

Cooking time

1

hour 

15

minutes

Calories per serving

624

kcal

Total time

1

hour 

30

minutes

Cook Mode

Keep the screen of your device on

INGREDIENTS

• 3 medium yellow onions, thinly sliced

• 1 head garlic, top trimmed (but unpeeled)

• 1 tsp Italian seasoning

• 1/2 tsp chili flakes (optional)

• 1/2 (80 g) sun-dried tomatoes in oil, drained and roughly chopped

• 3 tbsp olive oil

• Salt & pepper, to taste

• After baking:

• Juice of ½ lemon

• 2 handfuls baby spinach

• 2 tbsp chopped parsley, plus more for garnish

• 3/4 cup (180 ml) heavy cream or half-half

• 250 g (9 oz) short pasta (penne, fusilli, or rigatoni), cooked al dente

• Reserved pasta water (just a splash)

• 3/4 cup (75 g) grated mozzarella (or more, to taste)

DIRECTIONS

• Roast onions
• Preheat the oven to 375°F (190°C). In a large baking dish, combine the sliced onions, whole head of garlic (cut side up), sun-dried tomatoes, Italian seasoning, chili flakes, olive oil, salt, and pepper. Toss everything together, cover tightly with foil, and bake for about 1 hour (maybe a bit longer, depending on your oven). The onions should be soft, jammy, and caramelized.
• Cook the pasta
• While the onions roast, bring a large pot of salted water to a boil. Cook the pasta until al dente. Drain and set aside, reserving a little pasta water for later.
• Build the sauce
• Carefully remove the baking dish from the oven. Squeeze the roasted garlic cloves out of their skins and mash them directly into the softened onions. Add the lemon juice, spinach, chopped parsley, and cream. Stir gently to combine (the spinach will wilt from the heat).
• Mix with pasta
• Add the cooked pasta to the baking dish and toss everything together until well coated in the creamy sauce. Add a splash of pasta water.
• Top and bake again
• Scatter the grated mozzarella over the top. Return the dish to the oven and bake uncovered for 10–15 minutes, until bubbly and golden. Broil for 1–2 minutes at the end if you like a crispier, more browned top.
• Serve
• Let the dish rest for a few minutes before serving. Garnish with extra parsley and enjoy warm.

Notes

• Roast the onions low and slow until soft, jammy and golden. If they look too pale after an hour, give them another 10–15 minutes.
• Mozzarella makes the top melty and bubbly, but you can mix in parmesan or even gruyère for extra cheesy flavor.
• For a lighter version, swap the heavy cream for half-half or whole milk. To keep it dairy-free, use coconut cream or a plant-based substitute and top with your favorite vegan cheese.
• The nutrition information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice.

Nutrition Facts

• Total number of serves: 4
• Calories: 624kcal
• Fat: 32g
• Carbohydrates: 70g
• Protein: 16g

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