Preheat your oven to 425°F (220°C).
Wash the green beans thoroughly and trim the ends.
In a large bowl, toss the green beans with olive oil.
Add garlic powder, salt, and pepper to the bowl.
Mix until the green beans are evenly coated.
Spread the beans in a single layer on a baking sheet.
Bake in the preheated oven for 15-20 minutes.
Stir halfway through to ensure even roasting.
Remove from oven when they are tender and slightly crispy.
Drizzle with lemon juice and sprinkle with red pepper flakes and Parmesan cheese before serving.