Caramelized Onion Gruyere Squash

Featured in: One-Pan Comforts

This dish features tender roasted acorn squash halves generously filled with slowly caramelized onions and topped with melted Gruyere cheese. The sweetness from the squash and onions blends with the savory richness of the cheese, all enhanced by fresh thyme and parsley. Roasting the squash cut side down ensures optimal sweetness, while gradual caramelization of onions develops depth and balance. This comforting and elegant vegetarian main offers a harmonious combination of textures and flavors, perfect for any occasion.

Updated on Sun, 23 Nov 2025 15:32:00 GMT
Roasted Caramelized Onion Gruyere Acorn Squash, brimming with melted Gruyere and savory sweet onions. Save
Roasted Caramelized Onion Gruyere Acorn Squash, brimming with melted Gruyere and savory sweet onions. | coraloven.com

Acorn squash halves roasted until tender, stuffed with deeply caramelized onions and melty Gruyere cheese, and finished with fresh herbs—a comforting, gourmet vegetarian main perfect for any occasion.

This recipe combines the natural sweetness of roasted acorn squash with deeply caramelized onions and melted Gruyere cheese for a delicious and satisfying meal.

Ingredients

  • Squash: 2 medium acorn squash, halved lengthwise and seeded, 2 tablespoons olive oil, 1/2 teaspoon kosher salt, 1/4 teaspoon ground black pepper
  • Caramelized Onions: 2 large yellow onions, thinly sliced, 2 tablespoons unsalted butter, 1 tablespoon olive oil, 1/2 teaspoon kosher salt, 1/2 teaspoon granulated sugar, 2 teaspoons balsamic vinegar
  • Filling and Garnish: 1 1/2 cups Gruyere cheese, grated, 2 tablespoons fresh thyme leaves plus more for garnish, 1/4 cup chopped fresh parsley optional

Instructions

Step 1:
Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Step 2:
Brush the cut sides of the acorn squash with olive oil. Season with kosher salt and black pepper. Place squash halves cut side down on the prepared baking sheet and roast for 35 40 minutes or until the flesh is fork tender.
Step 3:
Meanwhile heat unsalted butter and olive oil in a large skillet over medium low heat. Add the sliced onions and kosher salt. Cook stirring occasionally for 30 35 minutes until the onions are deeply golden and soft. Sprinkle with sugar about halfway through to encourage caramelization.
Step 4:
Stir in the balsamic vinegar and fresh thyme. Cook for 2 minutes then remove from heat.
Step 5:
Remove squash from the oven and carefully turn cut side up. Reduce oven temperature to 375°F (190°C).
Step 6:
Evenly distribute the caramelized onions among the squash cavities. Top each half with grated Gruyere cheese.
Step 7:
Return the filled squash to the oven and bake for 15 20 minutes or until the cheese is melted and golden brown at the edges.
Step 8:
Remove from the oven. Garnish with fresh parsley and additional thyme leaves before serving.
Golden brown Caramelized Onion Gruyere Squash, a vegetarian delight, ready to be devoured with fresh thyme. Save
Golden brown Caramelized Onion Gruyere Squash, a vegetarian delight, ready to be devoured with fresh thyme. | coraloven.com

This dish is a family favorite that brings everyone together around the table for a comforting and flavorful meal.

Notes

Grate cheese yourself for the best melting texture. Easily doubled for meal prep or gatherings. Pairs beautifully with a green salad or crispy sourdough toast. Use certified gluten free cheese if needed.

Required Tools

Chefs knife, cutting board, baking sheet, parchment paper, large skillet, wooden spoon, grater

Allergen Information

Contains dairy (butter, Gruyere cheese). Naturally gluten free, always check cheese labels to confirm. Vegetarian friendly. No nuts or soy in the base recipe but verify all ingredient labels for cross contamination if needed.

Warm and comforting Caramelized Onion Gruyere Squash: a close-up shows the gooey cheese and tender squash. Save
Warm and comforting Caramelized Onion Gruyere Squash: a close-up shows the gooey cheese and tender squash. | coraloven.com

Serve this stuffed squash warm for a comforting dish that highlights seasonal flavors beautifully.

Recipe FAQs

How do you roast acorn squash for this dish?

Roast the squash halves cut side down at 400°F for 35–40 minutes until the flesh is fork-tender, which concentrates sweetness and enhances caramelization.

What’s the best way to caramelize the onions?

Cook thinly sliced onions slowly over medium-low heat with butter, olive oil, and sugar for 30–35 minutes, stirring occasionally to develop deep golden color without burning.

Can I substitute the Gruyere cheese?

Gruyere offers a rich, melty texture and nutty flavor, but you can use other melting cheeses like fontina or aged cheddar if preferred.

How do fresh herbs enhance the dish?

Fresh thyme added during onion caramelization and parsley garnish brighten the dish, balancing richness with herbal freshness.

Is this dish suitable for gluten-free diets?

Yes, this dish is naturally gluten-free; just ensure the cheese you use is certified gluten-free to avoid cross-contamination.

Caramelized Onion Gruyere Squash

Roasted acorn squash stuffed with caramelized onions, melted Gruyere, and fresh herbs for a comforting vegetarian main.

Prep time
20 minutes
Time to cook
60 minutes
Time Required
80 minutes
Created by Hannah Lewis


Skill level Medium

Cuisine Modern American

Makes 4 Portions

Dietary details Meatless, No gluten

What You Need

Squash

01 2 medium acorn squash, halved lengthwise and seeded
02 2 tablespoons olive oil
03 1/2 teaspoon kosher salt
04 1/4 teaspoon ground black pepper

Caramelized Onions

01 2 large yellow onions, thinly sliced
02 2 tablespoons unsalted butter
03 1 tablespoon olive oil
04 1/2 teaspoon kosher salt
05 1/2 teaspoon granulated sugar
06 2 teaspoons balsamic vinegar
07 2 tablespoons fresh thyme leaves

Filling and Garnish

01 1 1/2 cups Gruyere cheese, grated
02 1/4 cup chopped fresh parsley, optional

How To Make

Step 01

Preheat Oven and Prepare Baking Sheet: Preheat oven to 400°F. Line a baking sheet with parchment paper.

Step 02

Season and Roast Squash: Brush cut sides of acorn squash with olive oil and season with kosher salt and black pepper. Place squash halves cut side down on baking sheet and roast 35 to 40 minutes until fork-tender.

Step 03

Caramelize Onions: Heat unsalted butter and olive oil in large skillet over medium-low heat. Add sliced onions and kosher salt. Cook, stirring occasionally, 30 to 35 minutes until onions are golden and soft, adding sugar halfway through to deepen caramelization.

Step 04

Finish Onions: Stir in balsamic vinegar and fresh thyme leaves. Cook 2 minutes then remove from heat.

Step 05

Prepare Squash for Filling: Remove squash from oven and turn cut side up. Reduce oven temperature to 375°F.

Step 06

Stuff Squash Halves: Divide caramelized onions evenly among squash cavities. Top each half with grated Gruyere cheese.

Step 07

Bake Filled Squash: Return squash to oven and bake 15 to 20 minutes until cheese is melted and golden at edges.

Step 08

Garnish and Serve: Remove from oven and garnish with fresh parsley and additional thyme leaves before serving.

Needed utensils

  • Chef's knife
  • Cutting board
  • Baking sheet
  • Parchment paper
  • Large skillet
  • Wooden spoon
  • Grater

Allergy details

Check components for allergens, and get advice from a medical expert if you're unsure.
  • Contains dairy from butter and Gruyere cheese.
  • Naturally gluten-free, but verify cheese labels to ensure no cross-contamination.

Nutrition Details (each serving)

Details are for informational purposes, not medical use.
  • Kilocalories: 340
  • Fat content: 19 g
  • Carbohydrates: 32 g
  • Proteins: 12 g