Preheat broiler.
Split Kaiser roll, butter both sides and place on a broiler pan.
Toast both sides of roll, remove from oven and set aside.
Melt butter in small saucepan.
Sautee shallots in butter for 1 minute.
Reduce heat and add Worchestershire sauce, dijon mustard and black pepper until blended.
Add flour to create a roux.
Deglaze with white wine.
Add in cheeses and stir until blended. Add milk to loosen mixture if too thick. Stir until combined.
Spoon mixture evenly onto toasted buns, place into broiler to toast cheese topping (about 1 minute or until golden brown).
Sprinkle with sea salt to taste. Serve with your favorite spicy mustard.
