Caramelized Onion Gruyere Squash

Featured in: Comfort Food Classics

This dish features acorn squash halves roasted until tender and filled with richly caramelized onions. The filling is topped with melted Gruyere cheese and fresh thyme, creating a savory combination of sweet and nutty flavors. The slow roasting of squash enhances its natural sweetness while the onions develop depth through gentle caramelization. Finished with fresh herbs, this hearty vegetarian option is perfect as a comforting main dish for various occasions.

Updated on Sun, 23 Nov 2025 14:47:00 GMT
Golden, bubbly Caramelized Onion Gruyere Acorn Squash, a delicious vegetarian main course, ready to savor. Save
Golden, bubbly Caramelized Onion Gruyere Acorn Squash, a delicious vegetarian main course, ready to savor. | nibbromeals.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 sweetness of roasted acorn squash with rich caramelized onions and melty Gruyere cheese, creating a satisfying dish I love to serve during fall gatherings.

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.
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| nibbromeals.com

This dish brings my family together every fall, with its rich flavors and comforting warmth filling our home.

Notes

Roast squash cut side down to concentrate sweetness and enhance caramelization. Caramelize onions slowly over low heat to avoid burning and bitterness. 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

Nutritional Information

Calories: 340 per serving. Total Fat: 19 g. Carbohydrates: 32 g. Protein: 12 g.

Gruyere cheese melts perfectly atop the Caramelized Onion Gruyere Acorn Squash, a cozy dish for crisp fall days. Save
Gruyere cheese melts perfectly atop the Caramelized Onion Gruyere Acorn Squash, a cozy dish for crisp fall days. | nibbromeals.com

Enjoy this elegant vegetarian main with your loved ones for a cozy, flavorful meal.

Common recipe questions

How do I achieve deep caramelization of onions?

Cook sliced onions slowly over medium-low heat, stirring occasionally. Adding a pinch of sugar helps enhance the caramelization process and develop rich flavor.

What’s the best way to roast acorn squash for tenderness?

Roast squash halves cut side down at 400°F until the flesh is fork-tender, about 35–40 minutes. This concentrates sweetness and softens the texture.

Can I substitute Gruyere cheese with another variety?

Gruyere’s nutty melting qualities work best, but Emmental or fontina cheeses offer similar textures and mild flavors if Gruyere is unavailable.

How do fresh herbs enhance the dish?

Fresh thyme and parsley add bright, aromatic notes that balance the richness of cheese and sweetness of caramelized onions.

Is this dish suitable for gluten-free diets?

Yes, naturally gluten-free ingredients are used. Check cheese labels to ensure no gluten-containing additives.

Caramelized Onion Gruyere Squash

Roasted acorn squash filled with sweet caramelized onions and melted Gruyere cheese, topped with fresh herbs.

Time to prep
20 minutes
Time to cook
60 minutes
Overall time
80 minutes
Creator Ethan Cole


Level of difficulty Medium

Cuisine type Modern American

Serves 4 Number of servings

Nutrition info Meatless, No gluten

Ingredient list

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)

Cooking steps

Step 01

Prepare oven and squash: Preheat oven to 400°F. Line a baking sheet with parchment paper. Brush cut sides of acorn squash with olive oil and season with kosher salt and black pepper. Place squash halves cut side down on the baking sheet and roast for 35 to 40 minutes until fork-tender.

Step 02

Caramelize onions: Heat unsalted butter and olive oil in a large skillet over medium-low heat. Add sliced onions and kosher salt; cook uncovered for 30 to 35 minutes, stirring occasionally. Sprinkle sugar halfway through cooking to encourage caramelization.

Step 03

Finish onions: Stir in balsamic vinegar and fresh thyme leaves. Cook for 2 more minutes, then remove from heat.

Step 04

Fill squash: Remove squash from oven and turn cut side up. Reduce oven temperature to 375°F. Divide caramelized onions evenly among the squash cavities and top each half with grated Gruyere cheese.

Step 05

Bake filled squash: Return the stuffed squash to the oven and bake 15 to 20 minutes until cheese is melted and golden brown around the edges.

Step 06

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

Kitchen tools

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

Allergy details

Always check ingredients for allergens. Unsure? Talk to a healthcare expert.
  • Contains dairy from butter and Gruyere cheese
  • Naturally gluten-free; verify cheese labels to confirm

Nutrition details per serving

Details are shared for reference only. Reach out to your doctor with any health questions.
  • Energy (calories): 340
  • Total fat: 19 grams
  • Carbohydrates: 32 grams
  • Protein content: 12 grams