Leftover Corned Beef Reubens

  • Author: Sprinkles & Sea Salt
  • Yield: 2 sandwiches 1x


Leftover Corned Beef Reubens are the ultimate after St. Paddy’s Day sandwich. Loaded with slices of leftover corned beef, a tasty reuben sauce, caramelized onions and swiss cheese all sandwiched between thick slices of marbled rye bread. 



Caramelized Onions

2 tbsp unsalted butter

1 large onion, sliced thin

1 tsp salt


1/2 cup sauerkraut (drained)

2 tbsp sweet pickle relish

1 tbsp ketchup

2 tbsp mayonaise

1 tsp Worcestershire sauce

pinch of salt


2 tbsp unsalted butter

1 pound leftover corned beef

4 slices swiss cheese

6 slices marbled rye bread

caramelized onions



Caramelized Onions 

Melt the butter in a large skillet over medium heat

Add onions, sauté 2-3 minutes

Add salt, stir

Reduce heat to medium-low, continue to sauté for 30-35 more minutes, working with a wooden spoon, toss the onions every few minutes so they do not burn

Once onions are browned to your liking and sweet to taste, transfer them to a bowl and set aside

Do not clean the skillet, you will use it again


In a small bowl combine all sauce ingredients, mix well, set aside


Butter both sides of the 6 slices of bread

Put the same skillet that you cooked the onions in onto the stovetop over medium heat

Add the slices of corned beef, heat/brown on both sides for about 2 minutes*, set aside

Add 4 slices of bread to the skillet, toast on both sides, 1-2 minutes per side, set aside

Add the remaining 2 slices, toast on 1 side ,flip and add 2 slices of cheese to each toasted slice, allow cheese to melt (be careful not to burn the bread)

Take 1 slice of the toasted bread top with half of the corned beef slices, top with the slice of bread with the melted cheese, top with a generous helping of the sauce and caramelized onions, finish with the 3rd slice of toasted bread, repeat for the other sandwich


*you just want to heat the corned beef, you don’t want to cook out all of the grease or it will be too dry