celeriac fall soup

1 tablespoon neutral oil
1 shallot
1 medium celeriac/celery root
1/2 teaspoon fennel seeds
1 tablespoon dried tarragon
2 large sweet apples - peeled (I used Rosa Lee)
3 medium red potatoes - peeled
1 teaspoon jarred chicken bouillon
4 cups of water
3 tablespoons of butter
Salt to taste 

Chop celeriac, potatoes and apples into bite sized pieces. Dice shallot. 

Heat oil in a heavy bottom pan or Dutch oven. Add shallots and heat until translucent but not browned. Add fennel seeds and tarragon and warm through until fragrant. Add celeriac, potatoes and apples and stir. Add bouillon and water and stir. Bring to a boil and simmer on medium high, partially covered, for 20 minutes or until the celeriac is mostly softened. 

Use an immersion blender to process the soup until smooth. Stir in the butter until combined. Add salt to taste.