Set a large pot on medium low heat, add the oil and butter, letting the butter melt slowly
add the potatoes, celery and onions, stir to coat with butter and saute for 5 minutes
add the flour, stirring to coat. Stir constantly for 2 minutes
add the broth and milk and stir to combine
Bring to a boil then add the crab and corn
Reduce to simmer and let simmer for 5 -10 minutes or until the potatoes are how you like
Serve with a hearty bread like pumpernickel rye