In a large stockpot,over medium heat, melt the unsalted butter. Add the minced garlic and onion, until soft but not brown, stir occasionally for about 5 minutes.
Add in the parsnips, turnip, apples, and pear and stir well to blend all. Let cook for about 10 minutes to blend the flavors and the fruit will begin to break up.
Add in the vegetable stock, cumin, coriander, turmeric, sprigs of tarragon. and salt and pepper to taste. Bring to a boil, then reduce heat and cover, simmer over low heat for about 35-40 minutes or until vegetables are tender. Remove the 2 sprigs of tarragon from soup and discard.
Remove the pot from the heat and using an emulsion blender, blend soup until smooth. Adjust seasonings if needed. Can be served with a crostini, if desired.