Caramelized Onion Gruyere Squash

Featured in: Herbal Comfort Dishes

This dish features tender acorn squash halves roasted to bring out natural sweetness, then filled with slowly caramelized onions that add deep, rich flavor. Generous amounts of melted Gruyere cheese create a creamy, savory contrast. Fresh thyme and parsley finish the dish, offering a fresh herbal note. Perfect as a wholesome vegetarian main, it combines simple techniques like roasting and caramelizing to develop layered tastes and satisfying textures. The balance of sweet, savory, and fresh elements makes it a memorable meal for any occasion.

Updated on Sun, 23 Nov 2025 16:29:00 GMT
Golden caramelized onion Gruyere acorn squash, a comforting vegetarian main dish with melty cheese. Save
Golden caramelized onion Gruyere acorn squash, a comforting vegetarian main dish with melty cheese. | dunebasil.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 my go-to for cozy dinners, loved by family and guests alike for its rich flavors and hearty satisfaction.

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 Oven:
Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Prepare 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:
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 onions are deeply golden and soft. Sprinkle with sugar about halfway through to encourage caramelization.
Add Flavor:
Stir in the balsamic vinegar and fresh thyme. Cook for 2 minutes then remove from heat.
Prepare Filled Squash:
Remove squash from oven and carefully turn cut side up. Reduce oven temperature to 375°F (190°C). Evenly distribute caramelized onions among squash cavities. Top each half with grated Gruyere cheese.
Bake Filled Squash:
Return filled squash to oven and bake for 15–20 minutes or until cheese is melted and golden brown at edges.
Garnish and Serve:
Remove from oven. Garnish with fresh parsley and additional thyme leaves before serving.
Save
| dunebasil.com

My family always looks forward to this dish during autumn gatherings, appreciating the comforting warmth and rich flavors it brings to the table.

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 but always check cheese labels to confirm. Vegetarian-friendly. No nuts or soy in base recipe but verify labels for cross-contamination if needed.

Nutritional Information

Calories 340, Total Fat 19 g, Carbohydrates 32 g, Protein 12 g (per serving)

Roasted acorn squash stuffed with caramelized onions and Gruyere—a delicious flavor-packed vegetarian recipe. Save
Roasted acorn squash stuffed with caramelized onions and Gruyere—a delicious flavor-packed vegetarian recipe. | dunebasil.com

This recipe balances the sweetness of the squash with savory Gruyere and herbs for a deliciously satisfying meal.

Recipe FAQs

How do I caramelize onions properly for this dish?

Cook sliced onions slowly over medium-low heat with butter and oil, stirring occasionally, until they turn a deep golden brown and become soft, about 30–35 minutes. Adding a pinch of sugar halfway helps enhance sweetness.

What is the best way to prepare acorn squash for roasting?

Cut the squash in half lengthwise and remove seeds. Brush cut sides with olive oil, season with salt and pepper, and roast cut side down to concentrate sweetness and soften the flesh.

Can I substitute Gruyere cheese with another type?

Gruyere provides a creamy, nutty taste and good melt. Swiss or fontina cheeses are good alternatives that melt well and offer similar flavor profiles.

How do fresh herbs enhance this dish?

Fresh thyme added during onion caramelization brings warmth and earthiness, while parsley garnish adds brightness and color, balancing richness.

What sides pair well with this squash preparation?

A crisp green salad or crunchy sourdough toast complements the rich, savory flavors and provides contrasting textures.

Caramelized Onion Gruyere Squash

Roasted acorn squash stuffed with caramelized onions and melted Gruyere cheese topped with fresh herbs.

Prep Time
20 minutes
Time to Cook
60 minutes
Overall Time
80 minutes
Recipe by Dune Basil Lea Romano


Skill Level Medium

Cuisine Modern American

Makes 4 Portions

Diet Information Meat-Free, No Gluten

What You'll 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 Additional fresh thyme leaves for garnish
03 1/4 cup chopped fresh parsley (optional)

How to Make It

Step 01

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

Step 02

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

Step 03

Caramelize Onions: In a large skillet, heat unsalted butter and olive oil over medium-low heat. Add the sliced onions and kosher salt. Cook, stirring occasionally, for 30 to 35 minutes until onions turn deeply golden and soft. Sprinkle sugar halfway through to aid caramelization.

Step 04

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

Step 05

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

Step 06

Assemble Squash with Filling: Divide the caramelized onion mixture evenly among the squash cavities. Sprinkle grated Gruyere cheese over each half.

Step 07

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

Step 08

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

Essential Tools

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

Allergy Details

Review ingredients for allergies, and talk to your doctor if you're uncertain.
  • Contains dairy from butter and Gruyere cheese.
  • Naturally gluten-free but verify cheese labels to avoid gluten contamination.

Nutrition per serving

Nutritional details are for reference only. They're not a substitute for medical advice.
  • Energy: 340
  • Fats: 19 g
  • Carbohydrates: 32 g
  • Proteins: 12 g