Step 1: Preheat the oven to 425°F (220°C).
Step 2: Wash and trim the green beans.
Step 3: In a mixing bowl, combine the egg, olive oil, garlic powder, and salt. Whisk until mixed.
Step 4: Toss the green beans in the mixture until evenly coated.
Step 5: Spread the coated green beans on a baking sheet in a single layer.
Step 6: Roast for about 15-20 minutes, stirring halfway through.
Step 7: Sprinkle Parmesan cheese over the beans and roast for an additional 5 minutes.
Step 8: Serve and enjoy the delicious flavors!