Mix first 4 ingredients in medium bowl. Roll out crescent rolls and make sure creases are rolled out to make a sheet. Spread 1 tbs mustard over each sheet. Place 1/2 of pepperoni in a single layer atop mustard. Top pepperoni with half of cheese mixture.
Starting on opposite side roll pastry. Transfer to roll to baking sheet seam side down and refrigerate for 1hr. Cut roll into 1/4 inch slices.