- In a large pot, add potatoes, celery, onion, water and bouillon; bring to a boil.
- Reduce heat; cover and simmer for 20-25 minutes or until potatoes are tender; cool slightly.
- Place half of potato mixture in a blender; cover and puree.
- Repeat with remaining potato mixture; set aside.
- In same large pot, melt butter.
- Stir in flour, salt and pepper until smooth.
- Gradually add milk and bring to a boil.
- Boil and stir constantly for 2 minutes.
- Pour in potato puree and cook until heated thoroughly.
- Pour soup into individual serving bowls; garnish with sour cream and shredded cheddar cheese.