Heat the butter in a pan over medium heat until it melts and starts to bubble.

Add the onions to the pan and cook them, stirring occasionally, until they become soft and translucent, about 3-5 minutes.

Add the chicken pieces to the pan and cook for 6-8 minutes, stirring occasionally, until the chicken changes colour and is cooked through.

Sprinkle the salt, garlic powder, Cajun seasoning, black pepper, and oregano over the chicken, stirring the spices into the mixture. Cook for another 3-4 minutes to allow the spices to infuse the chicken.

Pour in the double cream, mixing it well with the chicken and spices. Cook the mixture for 4-5 minutes, stirring occasionally, until it thickens to your desired consistency.

Cut the pre-rolled puff pastry sheets into rectangles, ensuring they’re large enough to hold the chicken mixture.

Spoon the chicken mixture onto the center of the puff pastry rectangles, spreading it evenly.

Place another puff pastry rectangle on top, covering the chicken mixture, and press the edges to seal. Make a few slits at the top to allow steam to escape while baking.

Brush the top of the pastry with an egg wash (egg beaten with a little water) to give it a golden, glossy finish.

Sprinkle sesame seeds evenly over the top for added texture and flavour.