Caramelized Onion Gruyere Squash

Featured in: Cozy Cravings

This dish features acorn squash halves roasted to tender perfection, generously filled with slowly caramelized onions and topped with melted Gruyere cheese. Enhanced with fresh thyme and parsley, it offers a comforting, gourmet vegetarian main that balances sweetness and savory nutty flavors. Roasting the squash cut side down concentrates its natural sweetness while the onions are cooked low and slow for deep caramelization. The result is a flavorful, melty, herb-finished dish perfect for any occasion.

Updated on Sun, 23 Nov 2025 08:27:00 GMT
Golden Caramelized Onion Gruyere Acorn Squash, a savory vegetarian dish, shows roasted squash brimming. Save
Golden Caramelized Onion Gruyere Acorn Squash, a savory vegetarian dish, shows roasted squash brimming. | butterhollow.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 has become a favorite in my home for its rich flavors and ease of preparation.

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

Preheat:
Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Roast Squash:
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.
Caramelize Onions:
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.
Add Vinegar and Thyme:
Stir in the balsamic vinegar and fresh thyme. Cook for 2 minutes, then remove from heat.
Prepare Squash:
Remove squash from the oven and carefully turn cut side up. Reduce oven temperature to 375°F (190°C).
Fill Squash:
Evenly distribute the caramelized onions among the squash cavities. Top each half with grated Gruyere cheese.
Bake:
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.
Garnish:
Remove from the oven. Garnish with fresh parsley and additional thyme leaves before serving.
A delicious Caramelized Onion Gruyere Acorn Squash, ready to serve, features melted cheese and herbs. Save
A delicious Caramelized Onion Gruyere Acorn Squash, ready to serve, features melted cheese and herbs. | butterhollow.com

This dish always brings our family together around the table with warm smiles and full hearts.

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.

Allergen Information

Contains dairy (butter, Gruyere cheese). Naturally gluten free check cheese labels to confirm. Vegetarian friendly.

Nutritional Information

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

Warm, cheesy Caramelized Onion Gruyere Acorn Squash with tender squash and rich, golden onions awaits. Save
Warm, cheesy Caramelized Onion Gruyere Acorn Squash with tender squash and rich, golden onions awaits. | butterhollow.com

This recipe is sure to impress with its layers of flavor and comforting textures.

Kitchen Tips & Answers

How do I caramelize onions properly?

Cook sliced onions slowly over low to medium-low heat, stirring occasionally, until they turn deep golden and soft, usually about 30-35 minutes. Adding a pinch of sugar halfway can enhance caramelization.

What is the best way to roast acorn squash?

Brush squash halves with olive oil, season, and roast cut side down on a baking sheet at 400°F for 35-40 minutes until tender and fork-ready.

Can I prepare this dish ahead of time?

Yes, you can caramelize onions and roast squash in advance. Assemble and bake just before serving to keep the cheese melted and fresh.

What cheese works well with roasted squash?

Gruyere cheese melts beautifully and adds a creamy, nutty flavor that complements the sweet squash and caramelized onions perfectly.

How do fresh herbs enhance this dish?

Fresh thyme and parsley add a bright, aromatic finish that balances the sweetness of the squash and depth of the onions for a well-rounded flavor.

Caramelized Onion Gruyere Squash

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

Prep duration
20 min
Heat duration
60 min
Complete duration
80 min
Created by Ella Thompson


Skill level Medium

Heritage Modern American

Output 4 Portions

Eating preferences Meat-free, No gluten

What you'll need

Squash

01 2 medium acorn squash, halved lengthwise and seeded
02 2 tablespoons olive oil
03 ½ teaspoon kosher salt
04 ¼ teaspoon ground black pepper

Caramelized Onions

01 2 large yellow onions, thinly sliced
02 2 tablespoons unsalted butter
03 1 tablespoon olive oil
04 ½ teaspoon kosher salt
05 ½ teaspoon granulated sugar
06 2 teaspoons balsamic vinegar

Filling and Garnish

01 1½ cups Gruyere cheese, grated
02 2 tablespoons fresh thyme leaves
03 ¼ cup chopped fresh parsley, optional

Method

Phase 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, season with kosher salt and black pepper, then place cut side down on baking sheet and roast for 35 to 40 minutes until fork-tender.

Phase 02

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

Phase 03

Finish Onion Mixture: Stir in balsamic vinegar and fresh thyme, cook for 2 more minutes, then remove from heat.

Phase 04

Stuff Squash: Remove roasted squash from oven and turn cut side up. Reduce oven temperature to 375°F. Evenly fill squash cavities with caramelized onions and top each half with grated Gruyere cheese.

Phase 05

Bake Filling: Return filled squash to the oven and bake for 15 to 20 minutes until the cheese is melted and golden at the edges.

Phase 06

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

Kitchen tools needed

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

Allergy details

Always review individual ingredients for potential allergens and seek professional medical guidance if uncertain.
  • Contains dairy from butter and Gruyere cheese.
  • Naturally gluten-free, but verify cheese labels for gluten content.
  • Vegetarian-friendly; free from nuts and soy in core ingredients.

Nutrient breakdown per portion

Numbers shown are estimates only - consult healthcare providers for specific advice.
  • Energy: 340
  • Fats: 19 g
  • Carbohydrates: 32 g
  • Proteins: 12 g