Slice the whole 12 pack of buns horizontally into a top slab and a bottom slab, keeping the buns connected.
Cook the sliced shallots in butter until soft and sweet.
Mix the mayonnaise and Dijon mustard and spread over the bottom slab.
Layer the bottom slab with roast beef, shallots, and Swiss.
Place the top slab on, then brush with the melted butter, garlic, and Italian seasoning topping.
Bake at 350°F for 15 to 20 minutes until the cheese is melted and the tops are golden.
Cut into 12 sliders and serve with warm au jus for dipping.
For the au jus: add broth, Worcestershire, and soy, simmer about 3 minutes.