Soft spread butter (I used soft spread with olive oil added)
1 small onion (thinly sliced)
1 tablespoon sugar
Salt and ground black pepper
¾ cup dark beer (such as porter)
2 ounces deli-sliced corned beef (cut into strips)
2 teaspoons Worcestershire sauce
1 tablespoons stone ground mustard
4 Swiss cheese
4 slices marble rye bread
Instructions
In a large skillet over medium-high heat, melt the butter, add the onions sprinkled with the sugar, add ½ teaspoon salt, 1/8 teaspoon pepper, and cook until onions start to brown.
Add the beer to the onion mixture and continue cooking until the mixture is reduced to a light syrupy texture and onions are tender. Remove the skillet from the heat and mix in the meat, Worcestershire sauce, and mustard.
Using the soft spread butter 1 side of each slice of bread. Place 2 slices of the bread in a skillet, or on a griddle, buttered side down over medium heat. Place 1 slice of cheese on the bread and dived the meat mixture between the 2. Top with the other 2 slices of cheese; place the other 2 pieces of bread on top, butter side up, to form the sandwich.
Cook on each side until golden brown and cheese are melted.