My late paternal grandmother's recipe for green beans au gratin is a family favorite. Recipe may be halved and baked in slightly less time in an 8 x 8 baking dish (remember to use exactly half of all listed ingredients!).
WASH and de-string green beans; BLOT dry; SLICE off bean ends; CUT green beans to 2 1/2 inches in length; PREHEAT oven to 350°F; LIGHTLY butter a 2.5 quart dish or 9x13 baking dish; PLACE oven rack in center position; PREP the remaining saute ingredients (snip the bacon using kitchen shears, into small pieces); SHRED 12 ounces (3 cups) sharp cheddar cheese and set aside.
INTO a 3 quart heavy-bottomed pot over medium-low heat, add 1 tablespoon olive oil; ADD the chopped bacon, onion, mushrooms, minced parsley, minced garlic, SAUTE until onions have softened and mushrooms deepen in color.
ADD green beens; STIR in celery salt and fresh ground pepper; COVER and cook over medium-low heat, stirring occasionally, until green beans are crisp-tender and slightly lighter in color.
MELT 1/2 cup butter in a 2-3 quart saucepan over medium heat; STIR in 1/2 cup flour and cook slowly until bubbly but not browned.
COMBINE the half and half with the wine, then add the seasonings and whisk (mustard powder, sugar, salt and cayenne pepper); POUR mixture into roux while whisking constantly; COOK until fully thickened.
REMOVE from heat; STIR in the contents of one jar Kraft Old English sharp cheese spread, and 2 cups of the grated cheese until cheeses are melted and sauce is creamy.
FOLD the green bean saute mixture into cheese sauce until blended, without over-mixing (mixture will be thick); SPREAD mixture into prepared baking dish.
PLACE casserole into preheated 350°F oven; BAKE for 25 minutes.
SPREAD the 1 cup remaining shredded cheddar cheese over top of casserole; TOP casserole evenly with parmesan cheese, then one 2.8 ounce can French's French Fried Onions; BAKE casserole for 2-3 additional minutes just until cheese is melted and onion topping is golden browned (be careful not to burn onion topping!); LET set slightly before serving.