Cut the puff pastry into medium-sized triangles (around 2 inches).
2 puff pastry sheets
Bring a pot of water to a boil and add the chicken breasts, cook for 30 minutes, or until cooked through.
2 chicken breasts
Once it's cooked through, let it cool. Reserve the chicken broth and shred it with two forks.
Heat a non-stick skillet to medium-high and add the olive oil and butter. Once they are mixed and melted.
1 tablespoon olive oil, 1 tablespoon butter
Add the onion and garlic cloves. Cook for 5-7 minutes or until they soften.
1 onion, 2 garlic cloves
Add the celery and carrots and cook for a few more minutes. Add the peas.
1 cup celery, 1 cup carrots, 1 cup frozen peas
Add the flour and mix well. Add the heavy cream and mix well. Remove from the heat and season with thyme, salt and pepper. (You can adjust the thickness with the chicken broth if needed).
2 tablespoons all-purpose flour, 1 cup chicken broth, 2 cups heavy cream, 2 teaspoons thyme, Salt and pepper
Preheat the oven to 180ºC. Grease a baking dish and layer ⅓ of the puff pastry triangles at the bottom. Top with ½ of the chicken mixture. Now add another puff pastry layer and another chicken mixture layer. Finish with a last puff pastry layer and brush it with egg white.
1 egg white
Bake for 25 minutes or until golden brown.
Serve and enjoy!