Pulled beef pie with parsley mash

the pie is a bonus from making beef stock that I use to make french onion soup.Both are delicious and economical and make great winter warmers.Make the stock a couple of days ahead and let the fat separate on the top then skim it off.

Ingredients

1 kg	Beef bones, available at Asian butchers and very meaty,otherwise buy shin on the bone
2 large	Onions, chopped coarsly
3 medium	Carrots, chopped into chunks
2 stalks	Celery, chopped
1 clove	Garlic, sliced
1 pinch	Ground black pepper
1 Ltr	Warm water, or to cover

for the pastry

175 g	Plain flour
1 pinch	Salt
100 g	Butter
1 whole	Egg yolk
2 Tbsp	Water
1 squeeze	Lemon juice, mixed with egg yolk and water
1 pinch	Mustard powder
1 pinch	Cayenne pepper
1 sheet	Flaky puff pastry

pie filling and potato mash

1 whole	Beef, meat pulled from the meat bones (Main)
1 whole	Carrot, sliced
½ cup	Frozen peas
½ cup	Sweetcorn
1 Tbsp	Tomato puree
1 tsp	Mustard powder
1 Tbsp	Worcestershire sauce
1 cup	Beef stock, from your bones
1 pinch	Salt
¼ cup	Tasty cheese, grated
1 Tbsp	Plain flour
1 Tbsp	Butter
1 lb	Floury potatoes
1 handful	Parsley, chopped
1 drizzle	Olive oil, large
1 pinch	Salt & freshly ground pepper
1 Tbsp	Dijon mustard

Directions

1. Make the stock a couple of days ahead ( or keep a supply in your freezer) by putting all the ingredients into a stockpot and simmer 3 hours. Strain . Remove the meat from the bones and refrigerate. cool the stock the put in fridge until the fat has separated out to the top and formed a "biscuit" - remove fat and discard.Discard the vegetables.
2. make the pastry base by whizzing the flour, butter, mustard powder and cayenne pepper in a food processor. Add the egg yolk (keep the white), water and lemon juice and make into a paste. refrigerate 15 mins the roll out and line a pie plate. Refrigerate this while you make the filling. Shred the meat and soften in butter. add the flour and stir for a minute, it will be quite gooey. Add the stock,tomato paste, seasonings.add vegetables and simmer until carrot starts to soften. cool. fill the pastry case , top with cheese cover with the flaky pastry (put some slits in it to allow steam out). brush with egg white and cook 200 for 30 mins until pastry top is nicely browned.
3. boil potatoes until soft. Mash with olive oil, mustard, salt and pepper. stir in the chopped parsley. serve warm with pie.