Wash and boil potatoes. Peel and cut into cubes. Set aside.
MAKE THE WHITE SAUCE: Melt the butter, add the pimento pepper, onion and flour. Let simmer for 1 minute.
Add the milk and stir until it thickens, then turn off stove. Add the mushrooms and whole kernel corn to the cubed potatoes
Pour the white sauce over the potatoes and mix. Add the cheese, celery and sweet pepper and mix evenly
Place in a greased dish 12" x 8" x 2". Top with grated cheese and garnish with parsley and paprika.
Note: For the cheese I grated 1 cup of Cheddar Cheese to mix and I used grated Parmesan on the top.
Bake in a 350 degrees F oven for 30 minutes. Serve cool.