Heat butter in a large skillet over medium-high heat. Add the onions and cook for 4-5 minutes, or until the onions are starting to brown. Add the chicken and season with salt and pepper. Cook for 4-5 minutes or until the chicken is cooked through. Add in the buffalo sauce, tossing to coat.
Add 2 slices of provolone to each hoagie roll. Add an even amount of the chicken mixture to each. Wrap each tightly with some aluminum foil and place in the oven for 5 minutes. Remove and add a little blue cheese dressing.
Notes
To easily slice the chicken, place it in the freezer for 30 minutes.
While it is easy to make, I prefer just store-bought buffalo sauce.
To soften the bread and melt the cheese, wrap it in aluminum foil.