So, no more difficult than mashed potatoes, and prepared essentially the same way. You just need to add less butter and salt to your end product because parsnips are more flavorful. Peel and cut your parsnips and boil, just as you would to make mashed potatoes. Be careful not to overcook into mush. Drain, and either use a mixer or a potato masher to puree into a mash. Add salt, pepper, and cilantro garnish. Serve warm.