Bring a large pot of salted water to a boil and cook pasta as directed to al dente. During the last 2 minutes of cooking, add the broccoli florets to the water. Drain and set aside to cool in a large bowl.
Add diced yellow peppers, finely diced carrots, and chopped green olives to the pasta and broccoli.
Make the dressing by whisking together the mayonnaise, buttermilk, olive oil, and Dijon mustard. Pour the dressing over the pasta and vegetables, toss to combine.
Fold in the herbs and season to taste with salt and pepper, chill for at least an hour before serving.
Recipe by DomestikatedLife at https://domestikatedlife.com/2021/05/15/buttermilk-and-herb-macaroni-salad/