Preheat your oven to 350 and spray a 2 1/2 quart dish with cooking spray.
Wash, trim and cut green beans. Put in a large pot, cover with water and bring the water to a boil. Boil until green beans are soft; about 15-20 minutes. Drain and set beans aside.
Cook 6 strips of bacon. Once cooled, chop into bite sized pieces and set aside.
Chop onion. Saute in 2 TB of butter until translucent.
Stir in flour until smooth; cook for 1 minute. Remove from heat.
Stir in salt, sugar, sour cream and 1 cup of grated cheese.
Add green beans and bacon and incorporate well into the mixture.
Transfer to a 2 1/2 quart baking dish.
Crush crackers and measure out 3/4 cup; pour into a small dish.
Melt the remaining 3 TB of butter and pour into the dish with crushed crackers. Mix well.
Sprinkle the casserole with the remaining 1 cup of cheese, followed by the cracker topping.
Bake, uncovered, for 30 minutes or until the top is golden and the cheese is bubbly.
