In a large pot or Dutch oven, heat a splash of oil over medium heat. Add chopped onions, diced carrots, and sliced celery, sautéing for about 5 minutes until softened and fragrant.

Incorporate 1 kg of beef steak cut into cubes, browning the meat on all sides.

Sprinkle 2 tbsp of plain flour over the mixture, stirring well and cooking for 2 minutes.

Pour in 500 ml of Guinness stout, 500 ml of beef stock, and 2 tbsp of Worcestershire sauce. Stir and bring to a simmer.

Reduce heat and let it bubble gently for about 2 hours, stirring occasionally.

With 30 minutes left, stir in 150 g of mushrooms.

Preheat your oven to 200°C (400°F) and spoon filling into a pie dish.

Roll out 375 g of puff pastry to fit over the top and trim excess. Cut slits for steam.

Brush pastry with egg wash and bake for 25-30 minutes until golden.

Let the pie cool for a few minutes before slicing and serve.