Use a sharp knife to peel the outer skin from the dasheen. Cut the dasheen into large cubes. Bring the water to boil in a small saucepan over medium heat. Add the dasheen, salt, garlic, and parsley to the water. Cover and boil until dasheen is soft.
If the dasheen begins to cook away, raise the heat to help the water dissolve more quickly. Once the water is almost evaporated. Remove the pot from the heat. Allow it to cool for no more than 10 minutes. Use a whisk to whip in the butter unril the dasheen becomes fluffy. Dasheen should be light and fluffy like mashed potatoes.