Step 1

Caramelized Onions Heat the butter and olive oil in a medium non-stick skillet set over medium heat.Add the onions to the pan and satué until golden and caramelized, stirring every once in a while, not too often

Step 2

This will take between 45-60 minutes

Step 3

If you like your caramelized onions on the sweeter side, add 1-2 tsp brown sugar

Step 4

Add salt to taste

Step 5

If your onions are browning too quickly, turn the heat to medium low and add water to deglaze the pan 1 tablespoon at a time until they stop burning and start to caramelize again.Patty Melt In a small bowl mix the softened butter and mayonnaise together until combined

Step 6

Set aside.In a medium mixing bowl, mix together the ground beef, onion powder, garlic powder, 1 teaspoon salt, pepper and Worcestershire

Step 7

Form the meat mixture into 4 patties roughly the same shape of your slice of bread but a little bigger than the bread (they will shrink down when cooked and fit the bread perfectly) and sprinkle with remaining salt.Wipe out the pan used for the caramelized onions, or grab a second pan and heat it over medium heat

Step 8

Cook the beef patties on both sides until no longer pink in the middle.Butter each piece of sourdough with 1 tablespoon of the butter/mayonnaise mixture.Wipe out the pan again and place it back over the heat on medium-low

Step 9

Place 1 slice of Swiss cheese on each piece of bread (on the dry side, not the buttered side)

Step 10

Top each piece of cheese with a beef patty

Step 11

Divide the onions between the sandwiches and top with a 2nd cheese slice.

Step 12

Top each sandwich with the remaining bread slices butter side up.Cook until golden brown and crisp, and until the cheese is melted

Step 13

Carefully flip each sandwich over and repeat the cooking until golden brown and crips step

Step 14

Remove from the pan and slice in half

Step 15

Serve immediately.