Chicken and Leek Pie - Fresh-Pressed Olive Oil

Ingredients

• 1/2 cup whole wheat flour, plus more for rolling the dough
• 1 teaspoon sea salt, plus more for the vegetables
• 1 teaspoon freshly ground black pepper
• 1/4 cup extra virgin olive oil, divided use, plus more for the baking dish
• 2 large leeks, halved, cleaned, drained, and white parts cut into 1/2-inch half-moons, about 4 cups
• 1 large onion, peeled and diced
• 1 bell pepper, stemmed, seeded, and diced
• 2 celery stalks, diced
• 3 pounds skinless boneless chicken breasts, cut into approximately 1 1/2-inch cubes
• 2 cups half-and-half
• 1/4 cup chopped fresh flat-leaf parsley
• 2 teaspoons fresh thyme leaves
• 1 sheet frozen puff pastry, defrosted overnight in the fridge
• 1 egg