Preheat oven to 425℉. Line baking sheet with parchment paper.
Add the green beans, olive oil, salt, onion powder, pepper, and red pepper flakes to the baking sheet (we'll be adding the garlic later). Use tongs to toss, making sure everything is evenly distributed.
Roast in oven for 5-6 minutes. Remove from oven, add the garlic and toss to distribute. Return to oven and roast for another 5-6 minutes. The green beans should be almost done, but not quite. Add the Parmesan cheese and roast for another 3-4 minutes. Serve immediately.
Notes
You could add the garlic at the end with the Parmesan, but it won't be caramelized.
Frozen green beans are not recommended as the liquid they release may steam them instead of roasting them with crispy edges.
Omit the crushed red pepper flakes if you don't want them spicy.
Leftover green beans can be stored in an air-tight container in the fridge for up to 3-4 days.
Keyword Garlic, Green beans, Parmesan, Vegetables, Vegetarian