Preheat the oven to 400 degrees
In a bowl, toss the green beans in olive oil and about half the package of ranch seasoning, make sure they're coated evenly
Put into a small baking dish and bake uncovered for 30 minutes
Mix together the breadcrumbs, parmesan cheese, and more of the ranch seasoning. Slowly add butter, just until the mixture is crumbly but not too wet.
Pull the green beans out of the oven, and sprinkle the mixture over the top. Return to the oven for another 15 minutes until the topping is golden brown.