Preheat your oven to 425°F (220°C).
Rinse the green beans thoroughly and trim the ends.
In a large bowl, combine the green beans with olive oil, garlic powder, salt, and pepper.
Toss the green beans until they are evenly coated with the oil and seasonings.
Spread the green beans out on a baking sheet in a single layer.
Roast in the preheated oven for 15-20 minutes, or until tender and slightly crispy.
Halfway through roasting, stir the green beans to ensure even cooking.
When done, remove from the oven and sprinkle with sliced almonds.
Add lemon zest for a fresh flavor boost.
Garnish with fresh rosemary before serving.