Cut the sausage into 1/2-inch cubes and set aside.
Cover the potatoes with water in a small saucepan. Bring to a simmer and cook until tender; drain and reserve.
Meanwhile, heat 1/4 cup oil in a large saucepan over medium heat. Add the onion and cook, stirring 4 minutes, or until tender. Add the flour, 1/2 teaspoon salt, and 1/8 teaspoon black pepper; cook, stirring constantly for 1 minute.
Add the milk. Increase the heat to medium-high and bring to a boil, stirring constantly. Boil and stir 1 minute. Add corn and sausage and return to a boil. Reduce heat to medium-low and simmer 10 minutes.
Stir in potatoes and heat through. Season with salt, and pepper, and stir in 1 tablespoon chopped parsley.
Serve hot in bowls and garnish each with remaining parsley.