Caramelized Onion Gruyere Squash

Featured in: Cheesy Comfort Bites

This dish features acorn squash halves roasted until tender, then filled with deeply caramelized onions and topped with melted Gruyere cheese. The sweetness of the onions melds perfectly with the mild, nutty cheese, while fresh thyme and parsley add herbal brightness. Cooking involves slow onion caramelization for rich flavor and careful roasting to concentrate squash sweetness. Ideal for a comforting, elegant vegetarian main that's naturally gluten-free and perfect for any occasion.

Updated on Sun, 23 Nov 2025 16:50:00 GMT
Roasted Caramelized Onion Gruyere Acorn Squash, a delicious vegetarian main dish with golden cheese. Save
Roasted Caramelized Onion Gruyere Acorn Squash, a delicious vegetarian main dish with golden cheese. | williesnack.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 became a family favorite after I served it for a cozy autumn dinner.

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.
Melting Gruyere crowns the caramelized onions in this savory Acorn Squash recipe, perfect for a meal. Save
Melting Gruyere crowns the caramelized onions in this savory Acorn Squash recipe, perfect for a meal. | williesnack.com

This dish always brings smiles to our family table during the fall season.

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, comforting Acorn Squash with Caramelized Onion Gruyere: a gluten-free vegetarian delight. Save
Warm, comforting Acorn Squash with Caramelized Onion Gruyere: a gluten-free vegetarian delight. | williesnack.com

This dish is a perfect blend of savory sweetness and melty cheese, ideal for cozy dinners.

Recipe Questions & Answers

How do I achieve perfectly caramelized onions?

Cook onions slowly over medium-low heat with a combination of butter and olive oil, stirring occasionally. Add a pinch of sugar halfway through to encourage even caramelization without burning.

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

Brush squash halves with olive oil, season with salt and pepper, and roast cut side down until tender to enhance natural sweetness and texture.

Can I substitute Gruyere cheese?

Gruyere's melting quality and nuttiness are ideal, but Emmental or Fontina can be good alternatives with similar texture and flavor.

How to serve this squash dish?

Serve warm, garnished with fresh parsley and thyme, alongside a light green salad or crusty bread to balance richness.

Is this suitable for gluten-free diets?

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

Caramelized Onion Gruyere Squash

Roasted acorn squash filled with caramelized onions and melted Gruyere, enhanced by fresh thyme and parsley.

Prep time
20 min
Time to cook
60 min
Total duration
80 min
Created by Willie Cooper


Skill level Medium

Cuisine Modern American

Total yield 4 Number of servings

Dietary notes Vegetarian-friendly, 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 1/4 cup chopped fresh parsley (optional)
03 Additional fresh thyme leaves for garnish

How to make it

Step 01

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

Step 02

Roast Acorn 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 for 35 to 40 minutes until tender.

Step 03

Caramelize Onions: In a large skillet over medium-low heat, melt butter with olive oil. Add sliced onions and kosher salt. Cook, stirring occasionally, for 30 to 35 minutes until golden and soft, adding sugar halfway to promote caramelization.

Step 04

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

Step 05

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

Step 06

Fill Squash Halves: Distribute caramelized onions evenly among the squash cavities. Top each with grated Gruyere cheese.

Step 07

Bake Filled Squash: Return squash to oven and bake for 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.

Tools you'll need

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

Allergy details

Review ingredients for potential allergens and ask a medical expert if unsure.
  • Contains dairy from butter and Gruyere cheese.
  • Naturally gluten-free; check cheese labels to confirm.

Nutrition Details (per serving)

This nutritional info is for reference only. For health questions, check with a medical professional.
  • Energy: 340
  • Fats: 19 g
  • Carbohydrates: 32 g
  • Proteins: 12 g