# 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
→ Filling and Garnish
11 - 1 1/2 cups Gruyere cheese, grated
12 - 2 tablespoons fresh thyme leaves
13 - 1/4 cup chopped fresh parsley (optional)
# Step-by-Step Guide:
01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Brush cut sides of the squash halves with olive oil; season with kosher salt and black pepper. Place cut side down on the prepared baking sheet and roast for 35 to 40 minutes, until tender when pierced with a fork.
03 - Heat butter and olive oil in a large skillet over medium-low heat. Add sliced onions and kosher salt. Cook stirring occasionally for 30 to 35 minutes until deeply golden and soft, sprinkling granulated sugar halfway through cooking to enhance caramelization.
04 - Stir balsamic vinegar and fresh thyme into the caramelized onions. Cook for 2 more minutes, then remove from heat.
05 - Remove squash from oven and carefully turn cut side up. Reduce oven temperature to 375°F.
06 - Divide caramelized onions evenly among squash cavities. Top each half with grated Gruyere cheese.
07 - Return squash to oven and bake for 15 to 20 minutes until cheese is melted and golden at the edges.
08 - Remove from oven and garnish with chopped parsley and additional thyme leaves before serving.
