In a food processor, place the giardiniera, green olives, kalamata olives, olive oil, and vinegar, process until it is almost a paste. Set aside.
Cut the bread about ⅔ up from the bottom all the way across. Remove most of the bread from the bottom half, leaving about ½-inch thickness of bread remaining.
To the bread, add half of the olive spread, making sure to spread it out evenly.
Next, layer the provolone cheese, ham, salami, and prosciutto.
Top all the meat with the mozzarella.
Take the top of the bread and once again scoop out most of the bread leaving a ½-inch of the bread inside.
Spread the remaining olive mixture onto the top piece of bread then place it cut side down onto the sandwich.
With plastic wrap, wrap the sandwich tightly a few times so it is completely covered.
Place the wrapped sandwich sheet pan and put something heavy on top like a heavy skillet.
Place in the refrigerator for at least 4 hours to chill or even best overnight.
Remove from the refrigerator and remove the plastic wrap, cut into wedges and serve immediately.