Here's Chef Mike Bagley's recipe from JB's Sarnie Shoppe.
Ingredients:
2 Roasted Red Skin Potatoes
4 Cabbage Leaves
4 oz. Shaved Corned Beef
Marble Rye Bread
Sauce Ingredients:
2 oz. Stout
¼ Cup Horseradish
2 Cups Sour Cream
1 Tbsp. Sugar
Directions for the Sarnie:
1. Layer thin sliced potato, wilted cabbage leaves and corned beef on Rye bread.
2. Brush the bread with oil and place sandwich in a press.
Directions for the Sauce:
1. Whisk together stout, horseradish, sour cream and sugar.