This recipe was featured in the September 2015 issue of Every Day with Rachael Ray magazine.
In a food processor, pulse the giardiniera and olives into a finely chopped relish.
Heat a large skillet over medium to medium-high. Lightly butter the rolls. Press the cut sides onto the pan until evenly browned, 4-5 minutes. Add the folded mortadella to the skillet a few slices at a time and cook, turning with tongs, until lightly browned, about 2 minutes per side.