1. Bring potatoes and water to cover to a boil in a Dutch oven over medium-high heat. Cook potatoes 10 to 15 minutes or until tender. Drain and place in a large bowl.
2. Melt butter in Dutch oven over medium-high heat. Stir in frozen vegetables and chopped yellow onion; sauté onion mixture 6 to 8 minutes or until tender.
3. Add crabmeat, clams, next 6 ingredients, and potatoes. Reduce heat to medium, and bring to a boil; reduce heat to low, and simmer, stirring occasionally, 15 minutes or until thoroughly heated. Season with salt and pepper to taste. Let stand 10 minutes before serving. Garnish, if desired.
Note: For testing purposes only, we used McKenzie's Seasoning Blend for diced onion, red and green bell pepper, and celery and Campbell's Cream of Mushroom with Roasted Garlic Soup.