Whenever mama made this dish, I simply couldn't get enough

1, Preheat the oven to 450 F.
2. Arrange the bacon on a wire rack over a rimmed baking sheet. Bake for 15 minutes, or until crisp.
3. Remove the bacon from the oven and set aside. Carefully strain the fat.
4. Toss the beans, onion, salt and pepper together. Drizzle with about 3-4 tablespoons of the fat, and toss well to combine.
5. Arrange the beans in an even layer on a baking sheet. Roast for 20 minutes, tossing once to ensure they are cooking evenly.
6. Chop the bacon and scatter over the green beans for the last minute of cooking, just to heat through.