It's the ultimate stacked sandwich! You might lose track of how many layers there are, but that just adds to how flavorful it is!
Place all of the olive tapenade ingredients in a food processor and pulse blend until combined.
In a cast iron grill pan over medium-high heat, add some vegetable oil. You’re going to grill the zucchini slices in batches in one layer. Add 3 or 4 slices of zucchini and grill for 2 minutes on each side. Repeat until all the zucchini is grilled and then set aside.
Slice the top third off of the loaf of bread so that the bottom piece is larger. Using your fingers, hollow out the interior of the bread in both the bottom and top halves. Save the interior of the bread for another use like breadcrumbs.
Spread the olive tapenade in an even layer on the bottom loaf of bread. Then layer with 4 or 5 slices of vegan deli meat, 4 or 5 slices of vegan cheese and half the red onion slices. Fold 4 slices of grilled zucchini so it’s arranged in one even layer. Add half the roasted red pepper and then half the arugula. Sprinkle sea salt and ground pepper to taste. Repeat with a second layer of filling starting with the vegan deli meat. Then top with the top half of the bread.
Let it sit for at least an hour (or up to 4 hours) in the fridge before serving up. Slice into wedges just before serving.
You want a loaf of bread that is large, round and soft and chewy on the inside but has a crust on the outside.