Grandma's Green Bean Casserole

Preheat the oven to 350 degrees F (175 degrees C).

Make green beans: Melt butter in a large skillet over medium heat. Stir in flour until smooth, and cook for 1 minute. Stir in sour cream, onion, salt, and sugar. Add green beans, and stir to coat. Transfer mixture to a 2 1/2-quart casserole dish.

Spread Cheddar cheese over green bean mixture. Toss cracker crumbs and melted butter together in a small bowl; sprinkle over bean mixture.

Bake in the preheated oven until topping is golden and cheese is bubbly, about 30 minutes.