Soak potatoes and green beans in cold water for about 10 minutes.
In a small bowl, mix oil, onion, garlic, rosemary, parsley, salt, and pepper until well combined, set aside.
Next, drain potatoes and green beans then transfer potatoes in a baking dish and pour ⅔ of the oil mixture. Coat potatoes with the oil mixture and bake for 30 minutes uncovered.
With the remaining oil mixture, add it to the green beans and marinate while potatoes are in the oven.
After 30 minutes, remove potatoes from the oven, add the green beans and mix until combined. Be careful not to burn yourself and bake for another 20 minutes uncovered.
After 20 minutes or until potatoes are crispy, remove from oven and serve immediately.
Notes
*Preferably use red or Yukon Potatoes. If you don’t have that available, use Russet Potatoes.