Preheat the oven to 400°F (200°C) for the puff pastry topping.

Roll out the thawed puff pastry on a lightly floured surface to smooth it out. Cut into squares or circles, depending on your preference.

Place the puff pastry pieces on a baking sheet lined with parchment paper. Brush with beaten egg and bake for 12-15 minutes, or until golden and puffed. Set aside.

In a large pot or Dutch oven, heat the butter and olive oil over medium heat.

Add the diced onion, carrots, and celery. Sauté for 5-7 minutes, or until the vegetables are softened.

Stir in the minced garlic and cook for an additional 1 minute, until fragrant.

Sprinkle the flour over the vegetables and stir well to coat. Cook for 1-2 minutes to eliminate the raw flour taste.

Gradually whisk in the chicken broth, ensuring there are no lumps. Bring the mixture to a simmer.

Stir in the milk, heavy cream, shredded chicken, frozen peas, thyme, parsley, garlic powder, and onion powder. Simmer for 10-15 minutes, stirring occasionally, until the soup thickens slightly.

Season the soup with salt and freshly ground black pepper to taste.

Ladle the soup into bowls and top each with a piece of the baked puff pastry. Serve immediately and enjoy!