500g thickly sliced button or portabellini mushrooms
2 sheets puff pastry (enough to cover pie)
1 egg, beaten
Salt and pepper, to taste
Season beef with salt and pepper.Heat a drizzle of oil in a large heavy based pot.Add the beef and brown all over. Cook in batches to avoid the beef sweating.Set aside.
Turn heat down to medium and add a fresh drizzle of olive oil. Add leeks, celery, carrots and garlic. Cook until softened and sweet.
Add flour and stir through coating all the vegetables. Add beer, beef stock, thyme and bay leaves and stir to mix well. Bring to simmer and then cover.
Reduce heat to low and allow to cook for 2 hours until the beef if tender. Remove the lid and allow sauce to reduce until thickened. Add mushrooms and mix them in to evenly distribute.Taste and adjust seasoning.
Preheat oven to 200˚C. Pour pie filling into a pie / baking dish. (Roughly 25 x 20 x 4.5 cm)
Top with puff pastry.Cut out a few steam holes.Brush with egg wash and bake for 30-40 minutes until the pastry is deeply golden brown and cooked through.