Preheat the oven to 350°F.  In a medium pot, bring salted water to a boil.  Add the beans and let boil for 2-3 minutes.  Drain the beans and set aside.  (I prefer to leave the beans in their shell, but you can shell them with your fingers, if desired.)

In a medium bowl, add the beans, rosemary, garlic, and olive oil.  Season with the salt and gently toss to combine. Transfer the mixture to a baking sheet and roast for about 15 minutes.  Remove from the oven.

Arrange the beans on a platter and serve immediately.