In the USA, they learned how to cook sausages from German immigrants, who brought there the technology of making long and thin sausages. At that time, a hot dog consisted of two slices of bread and a sausage between them. The bread was needed to avoid getting dirty with grease and getting burned. After some time, slices of bread were replaced by a bun - this is a more recognizable version of a hot dog for us.
Step 1

Fry the onion in heated vegetable oil until golden brown.
Step 2

Prepare the sauce: mix ketchup, mayonnaise and mustard.
Step 3

Cut the hot dog bun lengthwise, grease the inside with butter and fry in butter until golden brown.
Step 4

Heat the sausage in a grill pan, place it in a bun and cover with fried onions. Sprinkle with cheese, put a pickle on top, pour sauce over it and serve.
Step 5

Make small cuts on the sausage to create a golden, appetizing pattern.