Heat oven to 350 degrees.
Grease a cookie sheet or jellyroll pan with olive oil.
If using fresh green beans, wash them and trim ends.
Dump green beans onto cookie sheet. Drizzle 2 tablespoons olive oil over the beans and sprinkle them with garlic powder, salt and pepper.
Use tongs or two forks—okay, I admit I use my fingers and think they work best—to toss the green beans and coat them evenly with oil and seasoning.
Bake green beans for 15 minutes.
Slide cookie sheet out of oven and turn green beans over to cook evenly.
Turn down oven to 325 degrees and continue to bake for another 5-15 minutes—I like the longer cooking time for drier, more wrinkly green beans.