In addition to being more specific about quantities of vegetables, I also scaled the recipe down to half the original amount. I tested the recipe both ways, and the end result is equally delicious, but I think 4-6 (normal) servings is a more reasonable quantity of soup than the original 6-8 (huge) servings. The arugula adds a spicy dimension to the soup. If you think you don't think arugula, you probably will still appreciate it here, but it can be left out, just add a little lemon juice to make up for the lost dimension.