Place the carrots, celery, onions, garlic, marjoram, basil, and stock in a medium-size saucepan.
Bring to a boil, then reduce heat, cover, and simmer for 10 minutes.
Add the milk and broccoli.
Return to a boil, reduce heat, then simmer for an additional 5 to 7 minutes or until the broccoli is tender.
Add the macaroni and nutmeg and heat through.
Remove some broccoli buds from the soup and place in a serving bowl.
Place the remaining soup in a blender and process on low speed, until the soup is smooth, holding down the lid so no hot liquid spills out.
Pour the soup into the serving dish.
Place the yogurt in a separate dish on the table so that each diner can garnish his or her soup, if desired.