In a bowl, combine chicken with salt, paprika, garlic powder, vinegar, and black pepper.
Let marinate for at least 30 minutes to absorb the flavors.
Heat 2 tbsp oil in a skillet.
Add the marinated chicken and cook until golden and fully cooked.
Remove from pan and set aside.
In the same skillet, melt the butter.
Add onions, garlic, carrots, and mushrooms. Sauté until softened.
Season with salt, paprika, garlic powder, oregano, and black pepper.
Sprinkle flour over the vegetables, stirring well to coat.
Slowly add chicken stock while whisking to avoid lumps.
Stir in milk, heavy cream, and sour cream.
Add cooked chicken back into the mixture. Let it simmer until creamy and slightly thickened.
Preheat oven to 200°C (390°F).
Transfer the filling into a pie dish.
Place the puff pastry sheet on top, pressing edges to seal.
Whisk egg and water together, then brush evenly over the pastry for a golden crust.
Cut small slits on top to allow steam to escape.
Bake for 25–30 minutes, or until the pastry is golden, puffed, and flaky.
Let cool for 5 minutes before serving. Enjoy your cozy, creamy chicken pot pie!