Brown beef in the oil, in batches, in a
large casserole or pan. Tip in the lardons,
shallots and celery, and fry for 10 mins
until softened and golden. Stir in the flour
until absorbed, crumble in the stock
cubes, then gradually stir in 1 litre water
and the Worcestershire sauce. Add herbs,
return the beef and any juices, cover and
simmer for 1 hr. Add carrots, cover and
simmer for 1 hr more until really tender.
Boil the potatoes in salted water until
tender. Drain well, return to pan over a
gentle heat and allow to steam-dry for
2 mins. Mash with the butter, cheese,
milk, mustard powder and seasoning.
Heat oven to 200C/180C fan/gas 6.
Strain beef and veg into a large colander
over a deep pan. Set sauce over a high
heat for 5 mins to reduce. Shred beef into
chunky pieces and transfer to a baking
dish with veg and bacon, and some
thickened sauce. Pipe or spoon on mash.
Bake for 30 mins until mash is golden and
crisp. The pie can be assembled and
chilled for up to 2 days, or frozen for up
to 3 months. If frozen, defrost thoroughly,
then bake as above, but for 50 mins-1 hr.