My Grandmother's Heavenly Chicken and Cheese Jalousie

Ingredients

• 2 cups (240 g) all-purpose flour
• 1/2 cup (113 g) unsalted butter, chilled and cubed
• 1/2 tsp (2.5 g) salt
• 1/4 cup (60 ml) cold water
• 1 cup (150 g) cooked chicken, shredded
• 1 cup (100 g) shredded cheese (cheddar, mozzarella, or your choice)
• 1/2 cup (80 g) cream cheese, softened
• 1/4 cup (60 g) sautéed onions
• Salt and pepper to taste
• 1 tsp (5 ml) garlic powder (optional)
• 1 tsp (5 ml) dried herbs (thyme or oregano)
• 1 large egg, beaten (for egg wash)
• Additional flour for dusting