Cook pasta according to package directions. Drain pasta, rinse with cold water, and drain again. Set aside.
Meanwhile, in a blender container or food processor bowl combine the 1 cup spinach, basil, garlic, cheese, salt, and pepper. Add oil and water; cover and blend or process until nearly smooth and mixture forms a paste, scraping down sides of container frequently. Combine the mayonnaise or salad dressing with the spinach mixture. Add to pasta and toss until well coated. Cover and chill for at least 4 hours or up to 24 hours.
To serve, line a salad bowl with spinach leaves and, if desired, radicchio leaves. Spoon salad into lined bowl. Sprinkle with chopped prosciutto and pine nuts. Makes 6 to 8 side-dish servings.