Peel the swede (a vegetable peeler is easiest) and chop into ½ inch chunks, then repeat with the carrots.
Put it all into a large saucepan and add enough cold water to just cover the vegetables. Add the salt and bring it to the boil, then reduce the heat and simmer for 20 minutes or until the vegetables are soft.
Drain, then pour the cooked vegetables back into the pan over a low heat and cook for 2 minutes, gently stirring so it doesn’t scorch, to evaporate some of the moisture.
Mash the swede either by hand or in a food processor (this will yield smoother results, though mashed swede will always be a bit chunky), along with the butter and nutmeg. Season with salt and pepper to taste.
Serve warm with a dusting of nutmeg.
The best and safest way to peel rutabaga is by using a vegetable peeler. I cut the bottom off so it has a stable surface and doesn't roll when cutting.Cut the swede and carrots the same size to make sure everything cooks evenly.Make sure you saute the carrots and swede over low heat to evaporate any excess moisture without burning.The finished product will always be a bit chunky due to the nature of the swede. To make it as smooth as possible, use a food processor or high speed blender to mash. Since there are no potatoes, it won't go gluey.