2 large onions, thinly sliced
few thyme sprigs
1陆 tbsp beef dripping or lard
150驳/5陆辞锄 plain flour
25g/1oz plain flour
dash Worcestershire sauce
dollop yeast extract, such as Marmite
2 bay leaves
600ml/20fl oz beef stock
salt and freshly ground black pepper
1 tsp crushed black peppercorns
1 tsp mustard powder
pinch salt
1 tsp salt
25g/1oz butter
4 free-range eggs, beaten
250ml/9fl oz milk
500g/1lb 2oz sirloin steak, at room temperature
sauerkraut and pickles, to serve