Place the diced potatoes in a pan. Pour in the broth. Bring to the boil, turn down the heat to low, cover and simmer for 15 to 20 minutes or until the potatoes are mushy.
While the potatoes simmer, prepare the rest of the ingredients. Melt half of the butter in a pan until bubbly. Add the chopped carrot, mushrooms and asparagus. Sprinkle in the thyme and sage, and a little salt and pepper. Go easy on the salt at this point -- if the potatoes are simmering in salted broth, you won't need to salt the vegetables and mushrooms heavily.
Cook the vegetables and mushrooms gently in butter for about two minutes.
When the potatoes are done, transfer with the broth into a blender. Process until smooth and thick.
Pour the pureed potatoes into the pan with the vegetables and mushrooms. Stir. Taste. Adjust the seasonings, as needed. If the soup is too thick, add more chicken bone broth, a quarter cup at a time. If you add broth, you'll have to adjust the seasonings again.
When the taste and texture of the soup is to your liking, turn off the heat. Cut the remaining butter into small cubes, drop into the soup and stir until melted.
Sprinkle the asparagus and mushroom soup with snipped parsley and serve.