Bring a large pot of salted water to a boil. Add the pasta and cook according to the package instructions. Drain and rinse under cold water until no longer hot; set aside.
To make the dressing: combine the mayonnaise, milk, sour cream, parsley, chives, lemon zest and juice, 1 teaspoon salt, ½ teaspoon pepper and 2 tablespoons of Parmesan in a small bowl. Set aside. Before tossing, splash in more milk if needed for thinning.
In a large bowl, combine the pasta, broccoli, tomatoes, peas, asparagus, carrot and green onions. Pour over the dressing and toss to coat. Top with the remaining tablespoon of Parmesan and some black pepper. Refrigerate for at least 4 hours and up to overnight.
NOTE: If you don’t care for broccoli, you can substitute cauliflower, or another favorite crunchy veggie. This would also be delish with some bacon added as well, or even diced chicken to make a light supper.
Adapted from: The Food Network / The Pioneer Woman