Grandma's Green Bean Casserole

We brought this to Thanksgiving dinner this year and it was sooo yummy! This one definitely takes the cake for the best green bean casserole I've ever had.

Grandma's Green Bean Casserole

2 tablespoons butter
1 tablespoon all-purpose flour
1/2 teaspoon salt
1/8 teaspoon pepper
1 teaspoon garlic powder
1 teaspoon white sugar
1/4 cup onion, diced
3/4 cup sour cream
3 (14.5 ounce) cans French style green beans, drained
2 cups shredded Cheddar cheese
1/2 cup crumbled buttery round crackers (I used Town House)
1 tablespoon butter, melted

Preheat oven to 350 degrees. Melt 2 tablespoons butter in large skillet over medium heat. Saute onions until tender and caramelized. Stir in flour until smooth, and cook for one minute. Stir in salt, sugar, pepper, garlic powder, sour cream and half of the cheddar cheese. Add green beans and stir well to coat (mixture may be somewhat thick). Transfer mixture to a 2 1/2 quart casserole dish and spread remaining cheese over the top. In small bowl, toss cracker crumbs and remaining butter. Sprinkle over the cheese. Bake for 30 minutes, or until the top is golden and cheese is bubbly.