Preheat the oven to 450°F (232°C). Line a baking sheet with parchment paper and set it aside.
In a large bowl, whisk together the egg, olive oil, garlic powder, and Himalayan salt until combined.
Add the cleaned, trimmed green beans to the bowl and gently toss so each bean is coated with the egg mixture; drain any excess egg from the bowl.
Add the grated Parmesan to the bowl and gently stir until the cheese is evenly distributed over the beans.
Spread the coated green beans in a single layer on the prepared baking sheet.
Bake for 15–20 minutes, until the beans are tender and edges are lightly browned and crisp.
