Preheat oven to 450 degrees F.
Mix the mustard and the buttermilk and set aside. Allow the flavors to blend in the refrigerator for 30 minutes.
On a clean workspace, place 1 sheet of phyllo dough, and lightly spray with butter flavored cooking oil. Sprinkle the top of the sheet with salt and pepper lightly. Lay a second sheet over the first one and repeat. Place 1 hot dog on the sheet of dough and roll tightly. Repeat process 3 more times.
Slice the ends off the dough wrapped dogs. Then slice the dough wrapped dogs into 3 equal segments.
Arrange sliced dogs on a wire rack over a baking sheet. Lightly spray with butter flavored cooking spray. Bake for approximately 10 minutes, or until dough is golden brown. Serve with mustard dipping sauce.