Preheat oven to 400° and spray a 9×13 baking dish.
Cut potatoes in half and add to a sealable gallon bag.
Add oil and seasonings to baggie and shake.
In a large frying pan, add sausage and water and cook over medium high heat until sausages have browned and most of water has evaporated.
Remove sausage from pan and when cool enough add to baggie.
Melt butter in frying pan and add onions and garlic, cook until onions are translucent.
Let cool for a few minutes and add to baggie and shake to mix.
Lastly, add green beans to baggie, shake to mix and then empty contents into prepared baking dish.
Cover with foil and place in the oven. Bake for 40 minutes or until potatoes are tender.