• 1  tablespoon  butter, plus extra for the baking dish
• 1  medium-size green bell pepper, finely chopped
• 1  medium-size yellow onion, finely chopped
• 1  10.75-ounce can condensed cream of mushroom soup
• 1  cup  mayonnaise
• 2  8-ounce packages cream cheese, softened
• 2  cup  grated Parmesan cheese
• 8  ounce  crabmeat, picked clean of shells
• 1/2  lb  shrimp, boiled, peeled, deveined and tails removed, chopped
•   salt and pepper to taste
• 1 1/2  cup  shredded Cheddar cheese (about 6 ounces)
• 2  celery stalks finely chopped

Preheat the oven to 375 F. Grease well a 13 by 9-inch baking dish.

Melt the butter in a medium saute pan. Saute the green pepper, onion, and celery until the vegetables are soft and the onion is translucent. Set aside to cool.

While the vegetables are cooling, in a large bowl, combine the soup, mayonnaise, cream cheese, and Parmesan cheese. Gently mix in the crab and shrimp, and season to taste with salt and pepper. Mix in the sauteed vegetables.

Pour the mixture into the prepared pan and top with the shredded cheddar. Bake the dip for 15 to 20 minutes, until the cheese is melted and the sides are bubbly.