# 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
05 - 2 large yellow onions, thinly sliced
06 - 2 tablespoons unsalted butter
07 - 1 tablespoon olive oil
08 - 1/2 teaspoon kosher salt
09 - 1/2 teaspoon granulated sugar
10 - 2 teaspoons balsamic vinegar
11 - 2 tablespoons fresh thyme leaves
→ Filling and Garnish
12 - 1 1/2 cups Gruyere cheese, grated
13 - Additional fresh thyme leaves for garnish
14 - 1/4 cup chopped fresh parsley (optional)
# How to Make It:
01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - 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.
03 - 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.
04 - Stir in balsamic vinegar and fresh thyme leaves into the onions. Cook for 2 more minutes, then remove from heat.
05 - Remove the roasted squash from the oven and carefully turn cut side up. Reduce oven temperature to 375°F.
06 - Divide the caramelized onion mixture evenly among the squash cavities. Sprinkle grated Gruyere cheese over each half.
07 - 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.
08 - Remove from the oven and garnish with chopped fresh parsley and additional thyme leaves before serving.
