Ingredients
1/2 cup finely chopped onion
1/4 cup butter, cubed
1 can (14-1/2 ounces) chicken broth
1 cup cubed peeled potato
2 celery ribs, chopped
2 medium carrots, chopped
1/4 cup Clamato juice
1/4 teaspoon lemon-pepper seasoning
1/4 cup all-purpose flour
2 cups milk
2 cups (8 ounces) shredded sharp cheddar cheese
1 can (6 ounces) crabmeat, drained, flaked and cartilage removed
1 cup cooked medium shrimp, peeled and deveined

Directions
In a large saucepan, saute onion in butter until tender. Stir in the broth, potato, celery, carrots, Clamato juice and lemon-pepper. Bring to a boil. Reduce heat; cover and simmer for 15-20 minutes or until vegetables are tender. 

In a small bowl, whisk flour and milk until smooth; add to soup. Bring to a boil; cook and stir for 2 minutes or until thickened. Reduce heat. Add the cheese, crab and shrimp; cook and stir until cheese is melted. Yield: 4 servings.

 
Source:  www.tasteofhome.com