Ingredients
4 Bratwurst sausages (or thick frankfurters) 
1 tbsp vegetable oil 
1½ medium onions, cut into rings 
1 tsp salt 
2 tsp caraway seeds 
300ml German beer (non-alcoholic is fine) 
Pepper 
4 hot dog buns 

Curry sauce 
1 tbsp vegetable oil 
½ onion, very finely chopped 
1½ tbsp curry powder 
½ tbsp paprika 
1 tsp ground cumin 
1 tsp ground turmeric 
200ml passata 
2 tbsp tomato ketchup 
2 tbsp brown sugar 
1½ tbsp vinegar - I like cider vinegar 
½ tbsp Worcestershire sauce 
Salt 
Pepper 

Method
Heat the oil in a pan and gently fry the onion over a medium heat for 5-7 minutes until soft and translucent.  Add the curry powder, paprika, cumin and turmeric and stir and cook for 30 seconds before adding the passata, tomato ketchup, sugar and vinegar and stir.  Bring to the boil then reduce the heat to medium low and cook for 20-30 minutes being very careful as it does have a tendency to spit so stir whenever it starts to spit too much. 

Put 1 tbsp of the oil into a heavy bottomed dish (I use my le Creuset) and brown the sausages over a medium high heat on all sides until golden brown.  Remove from the pan and put to one side. 

Add another tbsp of oil if needed and add the onions to the pan.  Stir to coat in the oil and sprinkle over the salt, stir and cook for around 10 mins until the onions begin to go a caramelised gorgeous brown colour.  Stir from time to time to stop them burning.   

When the onions are golden add the caraway seeds and stir thoroughly.  Leave for a minute or two to heat through and then add the beer.  Stir thoroughly and then add the sausages.  Turn the heat to high and bring to the boil.  When boiling reduce the heat to a medium low so the liquid is barely simmering, put the lid on and leave for 20 minutes, turning the sausages from time to time and carefully stirring the bottom. 

When you are ready to eat, remove the sausages, turn the heat to high and boil away any remaining liquid.  If you want your curry sauce super smooth sauce then blend.  Check for balance, this should be a bit like a ketchup so you do want it to be sort of sweet with an acidic edge. 

Cut the bun, put in the sausage and top with the onions and the sauce.