Caramelized Onion Gruyere Squash

Featured in: Comfort Food Love

Acorn squash halves are roasted until soft, then filled with slowly caramelized onions and topped with melted Gruyere cheese. Fresh thyme and parsley add aromatic depth, creating a comforting vegetarian main dish that pairs perfectly with light sides. The slow cooking of onions brings out deep sweetness, balancing the rich cheese and natural earthiness of the squash. Simple techniques and fresh ingredients combine to deliver a gourmet experience that’s suitable for any occasion.

Updated on Sat, 22 Nov 2025 13:07:00 GMT
Roasted Caramelized Onion Gruyere Acorn Squash, a golden image of cheesy baked goodness, perfect main course. Save
Roasted Caramelized Onion Gruyere Acorn Squash, a golden image of cheesy baked goodness, perfect main course. | tastyeffect.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 dish combines the sweetness of roasted acorn squash with the rich flavors of caramelized onions and Gruyere cheese, making it a personal favorite for cozy dinners.

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℉ (200℃). 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℉ (190℃).
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.
Warm, creamy Caramelized Onion Gruyere Squash, topped with herbs, offering a delightful vegetarian dinner. Save
Warm, creamy Caramelized Onion Gruyere Squash, topped with herbs, offering a delightful vegetarian dinner. | tastyeffect.com

My family loves gathering around this dish especially during fall when squash is in season, making every dinner feel special.

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

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.

Melting Gruyere and caramelized onions baked into acorn squash, an inviting presentation of comfort food. Save
Melting Gruyere and caramelized onions baked into acorn squash, an inviting presentation of comfort food. | tastyeffect.com

This recipe is a delightful blend of savory and sweet, perfect for impressing guests with minimal effort.

Recipe FAQ

What is the best way to caramelize onions for this dish?

Cook sliced onions slowly over medium-low heat with butter and olive oil, stirring occasionally until deeply golden and soft, about 30-35 minutes. Adding a pinch of sugar midway helps deepen sweetness.

How can I ensure the acorn squash roasts evenly?

Place squash halves cut side down on a lined baking sheet and roast at 400°F until fork-tender, around 35-40 minutes. This method concentrates sweetness and softens the flesh uniformly.

Can I prepare this dish ahead of time?

You can caramelize onions and roast squash in advance, then assemble and bake just before serving to maintain freshness and cheese melt.

What herbs complement the flavors in this squash dish?

Fresh thyme and parsley enhance the caramelized notes and rich cheese, adding brightness and herbal aroma to each bite.

Is there a recommended cheese substitute for Gruyere?

Swiss or Emmental cheeses offer similar melt and flavor profiles if Gruyere is unavailable. Choose good melting cheeses that balance sweetness.

Caramelized Onion Gruyere Squash

Roasted acorn squash halves with caramelized onions and Gruyere cheese, finished with thyme and parsley.

Prep duration
20 min
Cook duration
60 min
Complete duration
80 min
Created by Jane Miller


Skill level Medium

Heritage Modern American

Output 4 Portions

Dietary requirements Meat-free, No gluten

Components

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)

Directions

Phase 01

Preheat the oven: Set oven to 400°F and line a baking sheet with parchment paper.

Phase 02

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

Phase 03

Caramelize onions: In a large skillet over medium-low heat, melt butter with olive oil. Add onions and salt, cooking 30 to 35 minutes, stirring occasionally; sprinkle sugar halfway through to aid caramelization.

Phase 04

Finish onion mixture: Stir in balsamic vinegar and thyme, cook an additional 2 minutes, then remove from heat.

Phase 05

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

Phase 06

Fill squash cavities: Distribute caramelized onions evenly inside squash halves and top generously with grated Gruyere cheese.

Phase 07

Bake filled squash: Return filled squash to oven and bake 15 to 20 minutes until cheese melts and edges turn golden.

Phase 08

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

Necessary tools

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

Allergy details

Review each component for potential allergens and seek professional healthcare advice if uncertain.
  • Contains dairy from butter and Gruyere cheese.
  • Naturally gluten-free but verify cheese labels.

Nutritional information (per portion)

These values are approximate guides only and shouldn't replace professional medical consultation.
  • Energy: 340
  • Fats: 19 g
  • Carbohydrates: 32 g
  • Proteins: 12 g