Tessa's Cream of Potato Soup

In a pot combine chicken broth, chopped onion, potatoes and dillweed. Bring mixture to boiling. Reduce heat: cover and simmer for 10 minutes or till potatoes are tender. Place half of the potato mixture in a blender container or food processor. Cover and blend 30 to 60 seconds or till smooth. Pour into a bowl. Repeat with remaining mixture; set all aside. In the same pot melt the butter. Stir in flour, salt, and pepper. Add the milk all at once. Cook and stir till mixture is thickened and bubbly. Stir in the blended potato mixture. Cook and stir till soup is heated through. Season to taste with additional salt and pepper.