Cut the bread into approximately 1 inch cubes and spread on a baking sheet. Drizzle the bread with olive oil and a little salt.
Bake the bread until the cubes are just crunchy but do not squish or bend. They should not be as hard as croutons. The time this takes will depend on how dry/dense your bread already is (for me it typically takes 20-30 minutes). When done, set aside to cool to room temperature.
While the bread is baking, prepare the mix-ins. Either cut the cantaloupe into 1 inch pieces or use a melon baller to get balls of melon. Place in a large bowl. (If using a melon baller, see note).
Add the arugula to the bowl with the cantaloupe.
Tear the prosciutto slices into smaller pieces (4-5 pieces per slice) and add to the bowl. Cut the mozzarella if needed into bite sized pieces and add to the bowl.
In a small bowl, prepare the dressing by combining all of the ingredients. Whisk together and salt or pepper to taste.
When the bread is done and cooled to room temperature, add the bread and toss to combine.
Pour the dressing over the salad and toss to coat. Let the dressing sit on the salad ideally for 30 minutes in the refrigerator before serving so that it starts to soak into the bread. It will not make the bread soggy.
Ideally you want to use a denser bread for this salad, something more rustic with less air. The weight of the bread will vary based on exactly which one you use, but you want to aim for 6 cups in volume regardless.You can use any dressing that you like for this salad. Anything citrus would be great!I love using a melon baller to make the round balls of cantaloupe. You will need to use more than 1/2 of the cantaloupe to get enough pieces since not all of it will be used to get the shape. I love to use fresh mozzarella pearls because they are already in small pieces. But use any fresh mozzarella and cut as needed to be bite sized.