Start by preheating your oven to 425 degrees Fahrenheit. This high temperature is crucial for getting that signature snap and crispy exterior. While the oven heats up, line a large rimmed baking sheet with parchment paper or a silicone baking mat to prevent the cheese from sticking to the pan.
In a large mixing bowl, toss the trimmed green beans with the olive oil, minced garlic, salt, pepper, and onion powder. Use your hands or tongs to ensure every bean is evenly coated with the oil and spices. This ensures that the seasonings stay attached to the vegetables rather than falling to the bottom of the pan.
Sprinkle the grated parmesan cheese and the breadcrumbs over the seasoned beans. Toss everything together once more. The moisture from the oil will help the cheese and crumbs adhere to the surface of the beans, creating a beautiful crust as they roast.
Spread the green beans out in a single layer on your prepared baking sheet. It is important not to crowd the pan, as this would cause the beans to steam rather than roast. Place them in the oven and bake for 12 to 15 minutes, or until the beans are tender and the parmesan has turned a golden brown color. Serve immediately while hot and crispy.
