Preheat the oven to 450 degrees F (230 degrees C). Grease a shallow baking dish.
Mix soup mix and 1/4 cup olive oil together in a large zip-top bag. Add potatoes and coat well. Transfer to the prepared baking dish.
Roast in the preheated oven, uncovered, for 30 minutes. Mix in green beans and portobello mushrooms. Sprinkle in carrots and drizzle with remaining 1 tablespoon olive oil. Continue to roast until beans and potatoes are tender, about 10 minutes more.