How to Make It
Heat the oven to 350°. Put the bread cubes on a baking sheet and toss them with 3 tablespoons of the oil and 1/8 teaspoon each salt and pepper. Bake, stirring the croutons occasionally, until they are crisp and brown, 10 to 15 minutes.
Meanwhile, in a large glass or stainless-steel bowl, whisk together the vinegar, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Add the remaining 6 tablespoons oil slowly, whisking.
Add the watercress and the salami to the dressing and toss to combine. Toss in the croutons. Put the salad on plates and crumble some of the goat cheese over each serving.
Mix some arugula in with the watercress leaves; just be sure to have a total of about three-and-a-half quarts of greens.
Use strips of pepperoni instead of salami.
Add some chopped tomato.