Save 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 at my home especially during the fall when squash is fresh and in season.
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.
Save Every time I make this dish, my family gathers around the kitchen smiling and eagerly waiting to taste the warm, cheesy squash.
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.
Save This Caramelized Onion Gruyere Squash is a perfect blend of sweet and savory and will satisfy both vegetarians and cheese lovers alike.
Kitchen Guide
- → How do I caramelize onions properly?
Cook thinly sliced onions slowly over medium-low heat with butter and oil, stirring occasionally, until they turn deep golden and soft. Adding a pinch of sugar helps enhance sweetness.
- → Can I use a different type of squash?
Yes, similar squash varieties like kabocha or butternut can work, but adjust roasting times to ensure the flesh becomes tender.
- → What cheese works best for melting in this dish?
Gruyere melts beautifully, offering a nutty flavor and creamy texture, but alternatives like fontina or mozzarella also work well.
- → How do I ensure the squash is tender when roasting?
Roast the squash cut side down on a lined baking sheet at 400°F until the flesh is easily pierced with a fork, typically 35-40 minutes.
- → Can I prepare this ahead of time?
Yes, caramelize the onions and roast the squash in advance, then assemble and bake shortly before serving for best freshness.