Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Heat 1 tablespoon of olive oil in a large skillet over medium heat and add the sliced yellow onions. Caramelize for about 15-20 minutes until golden brown.

In another skillet, heat the remaining olive oil over medium-high. Add cubed butternut squash and sauté for 10-15 minutes until tender and slightly caramelized.

In a mixing bowl, combine the caramelized onions, sautéed butternut squash, fresh thyme, salt, and pepper.

Roll out the puff pastry on the prepared baking sheet. Spread the filling evenly and sprinkle crumbled goat cheese on top.

Bake for 25-30 minutes until the puff pastry is golden brown and flaky.