01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large mixing bowl, toss green beans with olive oil, minced garlic, salt, black pepper, and crushed red pepper flakes until well coated.
03 - Spread seasoned green beans evenly in a single layer on the prepared baking sheet.
04 - Roast green beans for 15 minutes, stirring halfway through, until tender and lightly browned.
05 - Sprinkle shredded mozzarella and grated Parmesan evenly over the roasted green beans.
06 - Return baking sheet to oven and roast for an additional 5 minutes, until cheese is melted and golden.
07 - Remove from oven. Garnish with chopped parsley if desired. Serve immediately.