posted by Polar Bear 06-16-103 1:11 PM 
  
Green Bean Casserole from Scratch 
1 lb fresh thin green beans (haricot verts) 
1 med onion 
1 c buttermilk 
1 tsp cayenne 
1 tbsp salt (divided) 
1-1/2 tsp black pepper (divided) 
2 c + 2 tbsp unbleached flour (divided) 
6 c vegetable oil (for frying) 
3 tbsp butter 
8 oz mushrooms 
1 c light cream (or 1/2 c each milk and heavy cream) 
Trim green beans and cut into 1 inch pieces; cook in salted boiling water to cover until just tender, about 10 minutes. Rinse with cold water and drain while preparing recipe. 
Slice onion thinly and cut in eighths; stir in buttermilk, cayenne, 2 tsp salt and 1 tsp black pepper; let stand 10 minutes and drain (discard marinade). Toss 1/4 onions with 2 c flour; shake to remove excess. Fry in 360 degree oil until crisp and browned, about 2 minutes; drain on paper towels, sprinkling with 1/8 tsp salt. Fry remaining onions in three batches. 
Cut mushrooms in 1/4 inch dice. Saute in butter with remaining 1/2 tsp each salt and pepper until liquid evaporates, 10 to 15 minutes. Add 2 tbsp flour and saute until bubbly, 2 to 3 minutes. Gradually stir in light cream and cook until thickened, 3 to 5 minutes. 
Combine beans, mushroom sauce and 3/4's the onions. Spread in a lightly greased 10 inch square baking dish; sprinkle with remaining onions. Bake 15 minutes in 400 degree oven. Broil briefly, until golden brown. Serve immediately.