For the Filling:

• 1 lb boneless, skinless chicken breast or thighs (cooked and shredded)
• 1 package (16 oz) potato gnocchi
• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• 1 small yellow onion, diced
• 2 cloves garlic, minced
• 2 carrots, peeled and diced
• 2 celery stalks, diced
• 1/2 teaspoon dried thyme
• 1/2 teaspoon dried rosemary
• 1/4 cup all-purpose flour
• 2 cups low-sodium chicken broth
• 1 cup whole milk or half-and-half
• 1/2 cup frozen peas
• 1/4 cup chopped fresh parsley
• Salt and black pepper to taste

For the Topping:

• 1 sheet puff pastry, thawed
• 1 egg, beaten, for egg wash