Ingredients:

• Rump steak - about 6oz (uncooked) per person
• 1 bottle of good ale, porter or stout
• ½ tsp Herbs de Provence
• 2-3 tsp of sunflower oil
• 1 medium or ½ large onion
• ½ lb Chestnut or large flat mushrooms
• 1 tbs of plain flour
• 1 tsp of english or 3 tsp of grainy mustard
• 1 pack puff pastry.

The night before:
Dice your steak into good mouthfuls and put into a bowl with the bottle of beer and herbs.

2 hours before:
Drain the steak into a colander or sieve, reserving the beer (place the sieve over a saucepan).

Method:
Put a heavy based pan onto the stove under a medium heat with the oil. Coat the (now dry) steak with the flour. The easiest way is to get one of the plastic bags that your veg comes in, put the meat in, then the flour, twist the top enclosing a fair amount of air and give a good shake.  Chop the mushrooms into bite-sized pieces.
Put steak and all of the mushrooms into oil and seal (brown all over) making sure that bits of the meat get seared (important for flavour).  If you have cheap meat, make sure you have driven off all the water.
Dice the onions finely.
Take out the steak & mushrooms and put into a bowl.
Put more oil into the pan to heat and add the onions. Cook until translucent.
As the onions become translucent, add all the mushrooms and the steak.
Slowly add the reserved beer, stirring constantly, so that the flour absorbs the liquor.
When all the beer is in (covering everything), cover and simmer for about 40 mins.
Remove cover and continue simmering whilst reducing the stock to a gravy-like consistency.  Add the mustard after another 10 minutes.
Put the oven onto gas mark 7.
Take a pie dish (whatever) and cut out a pastry lid from the puff pastry. If the pie dish is large, I use an egg cup in the middle of the pie dish to stop the pastry drooping.
Put the contents of the casserole into the pie dish, put over the puff pastry and add any off cuts of pastry as decoration.
Make two cuts into the pastry to let the steam escape.  Optionally (I don't), brush the pastry with milk/egg yolk.
Place pie dish into the oven for 25-30 mins, by which time the pie crust should be nicely risen and a golden colour.

Serve with mash with 4 oz of cheese added whilst mashing plus whichever green vegetable you like - I normally use green beans. More of the same beer is the best accompaniment.