Pulse the olives in a food processor until finely chopped; transfer to a small bowl (be sure to scrape out every last bit). Wipe out the food processor bowl. Pulse the giardiniera in the processor until finely chopped; transfer to a medium bowl, add the mayonnaise and stir to combine.
Put an 18-inch-long piece of plastic wrap on the counter. Arrange 9 slices of the bread on the plastic in a 3-piece-by-3-piece square, overlapping the pieces by 1/4 inch. Press the overlapping parts together firmly with your fingers so they stick together. Cover the bread with another 18-inch-long piece of plastic wrap, and roll over the bread several times with a rolling pin, pressing to adhere and flatten the bread. Remove the top piece of plastic, and spread half the giardinera mayonnaise over the bread in an even layer.
Fold half the mortadella slices in half, and place them on the bottom third of the bread square. Place half the salami slices on the mortadella, then add half the provolone slices (overlap the slices in each row). Spread half the chopped olives evenly over the cheese.
Tightly roll up the bread and filling, starting at the bottom, using the plastic wrap to keep it together and tucking the filling in tightly as you go. Tighten the plastic wrap at the ends and pinch the ends together until you have made a very tight roll. Repeat with the remaining 9 slices of bread and fillings. Refrigerate for at least 2 hours up to overnight.
Unwrap the logs, and slice each into twelve 3/4-inch slices.
Copyright 2014 Television Food Network, G.P. All rights reserved.