Put all ingredients in a very large mixing bowl. I mix my italian dressing mix with red wine vinegar, water and olive oil. then I combine the italian dressing with the mayo & 2 tablespoons of ranch dressing mix. Add those to the pasta and other ingredients and mix to coat everything. I chill this overnight before serving! The flavors have time to blend very well when chilled overnight!
it sounds like a lot of mayo I know, but with that much food it comes out just enough to coat and flavor well! Enjoy! I use my DIY ranch dressing mix and my DIY italian dressing mix