Make the White Sauce:
Melt butter in a saucepan or pot over a very low fire.
Add onion and allow to cook for 1 minute.
Stir in the flour gradually to a smooth paste.
Pour in the milk. Continue stirring.
Add white pepper.
Allow to simmer until thick. Stir gradually. Set aside.
Note: It is normal for the milk to form a “skin” while it cools. So don’t worry too much about that.
Boil macaroni. Drain. Place in a deep bowl. Then add the grated pumpkin. Mix well.
Note: We used raw grated pumpkin and not cooked pumpkin. This was to avoid overcooking the pumpkin and not deriving much nutritional value from the vegetable.
Add the white sauce, Angostura bitters, ketchup, celery, pimento, and 1 cup of cheese. Mix well.
Preheat oven at 400 degrees F.
Pour mixture in a well greased casserole dish.
Garnish with sweet pepper and the remainder of cheese.
Bake in 350 degrees F oven till golden brown, about 20 to 30 minutes. Allow to cool 10 minutes then Serve.