From a Jacques Pépin recipe; the original called for anchovies, which you can add if you are so inclined.

Slice the pillow loaf in half lengthwise so that you have a top and a bottom.
Mix the olive oil, minced garlic, chopped olives, and chopped anchovies together; spread on both halves.
Salt and pepper both halves.
On the bottom half, layer the rest of the ingredients.
Now, put the top half back on and wrap the whole thing very tightly in plastic wrap.
Put on a big plate and cover with another big plate.
Here comes the fun part.
Place the sandwich on a very sturdy shelf in your refrigerator and cover the top plate with heavy books or weight-lifter's plate weights.
Keep in refrigerator overnight, turning the sandwich about halfway thru.
The juices from the vegetables will permeate the bread, but not make it soggy.
Slice into wedges to serve.