Preparation Cook broccoli stems in large pot of boiling salted water 2 minutes. Add florets and cook until stems and florets are crisp-tender, about 2 minutes longer. Using slotted spoon, transfer broccoli to strainer. Refresh under cold water. Drain. Bring same pot of water to boil. Add pasta; cook until just tender but still firm to bite. Drain. Rinse under cold water. Whisk mayonnaise, sour cream, and vinegar in large bowl. Add half of Gorgonzola cheese. Using rubber spatula, mash until cheese is almost smooth. Stir in remaining cheese. Add pasta, green onions, celery, parsley, and broccoli; toss to coat. Season salad to taste with salt and pepper. Cover and refrigerate until cold, about 2 hours. (Can be made 1 day ahead. Keep refrigerated.)
Preparation Cook broccoli stems in large pot of boiling salted water 2 minutes. Add florets and cook until stems and florets are crisp-tender, about 2 minutes longer. Using slotted spoon, transfer broccoli to strainer. Refresh under cold water. Drain. Bring same pot of water to boil. Add pasta; cook until just tender but still firm to bite. Drain. Rinse under cold water. Whisk mayonnaise, sour cream, and vinegar in large bowl. Add half of Gorgonzola cheese. Using rubber spatula, mash until cheese is almost smooth. Stir in remaining cheese. Add pasta, green onions, celery, parsley, and broccoli; toss to coat. Season salad to taste with salt and pepper. Cover and refrigerate until cold, about 2 hours. (Can be made 1 day ahead. Keep refrigerated.)