Ingredients
4 burger patties
2 tbsp oil
4 pretzel buns
Gherkins, 8 spears
2 tbsps American mustard

Ingredients for the beer cheese
20g butter
30g flour
120ml milk
80ml German beer (non-alcoholic is fine)
1 tsp Worcestershire sauce 
1 tsp wholegrain mustard
½ tsp dijon mustard
75g strong cheddar cheese, grated
75g gruyere, grated
Salt and pepper to taste

Ingredients for the onions
2 medium onions, cut into rings
1 tsp salt
1 tsp caraway seeds
250ml German beer (non-alcoholic is fine)
1 tsp sugar
Pepper 

Method
Start with the onions.  Add a tbsp of oil to a pan over a medium heat and when hot, add the onions to the pan.  Stir to coat in the oil and sprinkle over the salt, stir and cook for around 10 minutes, stirring from time to time until the onions are beginning to caramelise and are a gorgeous brown colour.   

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 and turn the heat to high to bring to the boil.  Once boiling, cook until the beer has reduced to a sticky glaze and the onions are soft and sticky.  Stir from time to time to stop the onions burning.

Turn now to the cheese sauce.  Melt the butter in a small saucepan over medium heat and when melted, add the flour and whisk until a paste forms. Take the pan off the heat and slowly whisk in the milk, making sure there are no lumps.  Add the beer and stir until incorporated.  Cook until the sauce is thick, stirring all the time, making sure you get into the edge of the pan.  Lower the heat and cook for 5 minutes stirring from time to time to stop a skin forming on the sauce.  Turn off the heat and add all of the other ingredients, mixing through until the cheese melts.  Check the seasoning and add salt and pepper to taste.  Turn the heat back on low to keep warm while you finish off.

It depends on how big your pan is to how many patties you can cook at one time, you don’t want to over fill as the burgers do need space to caramelise.  You can either cook in 1 pan if big enough, in 2 pans at the same time or, heat the oven and cook in batches.

To cook, take a frying pan and put in a tbsp oil, when hot put in the patties and push down with your spatula.  Cook on a medium heat for 3-5 minutes until they are brown and turn, cook again for 3-5 minutes and turn again and cook for a final 3 minutes.  Your burger should now be cooked perfectly but if it is not, just carefully cook a little longer.

Toast your bun, put a spoonful of the cheese sauce on to the bottom bun and top with 2 gherkin spears.  Put the burger patty on top of the gherkins and add a very generous spoonful (or two) of the cheese sauce on top of the patties and top with the onions. Put ½ tbsp of mustard on the bun lid and put on top of the onions.