Start by making the sauce. In a medium saucepan, make a roux of butter and flour over low to medium heat. Whisk until the flour is combined and is pasty in texture. Place the half & half in a microwave oven and gently warm it. Over a low heat, add the half & half to the roux and whisk together until all of the flour is dissolved and the sauce is creamy. Add the remaining sauce ingredients and whisk together just until they are combined. Remove from heat and set aside.

In a Dutch oven, par-boil the diced potatoes until they are fork tender. Drain and set aside. Coat the Dutch oven with the vegetable oil and pre-heat. Sauté the onion, celery, bell pepper and scallions until tender. Lightly salt & pepper during this process.

Add the potatoes and corn. Stir gently to incorporate. Add the sauce mixture and, on low heat, simmer for 5 minutes. Add the crab meat and the shrimp. Cook (still on low heat) until the shrimp are pink and beginning to curl, usually 5 to 7 minutes. Check for seasoning and salt & pepper to taste.

Spoon into bowls and garnish with scallion greens. This is tasty served with crusty bread for dunking.