Butternut Squash Tart with Gruyère | For 8 Servings

Ingredients

• 1 sheet (250g) all-butter puff pastry, chilled
• 1 small (700g) butternut squash, peeled and cubed into 1/2-inch pieces
• 2 large (400g) yellow onions, thinly sliced
• 2 tbsp (30ml) extra virgin olive oil
• 1 tbsp (14g) unsalted butter
• 1 tbsp (15ml) balsamic vinegar
• 1 tsp (4g) brown sugar
• 1 cup (100g) Gruyère cheese, freshly shredded
• 2 tbsp (4g) fresh sage leaves, chiffonade
• 1 tsp (6g) kosher salt
• 1/2 tsp (1g) freshly cracked black pepper
• 1 large egg, beaten