Pressure cook the swede / rutabaga whole and unpeeled using my method.
Discard hot water and add 250 ml cold water.
Let the swede / rutabaga cool down enough to handle (or do this ahead of time and store in the fridge) then dice into big chunks.
Place the diced swede / rutabaga and the chopped up carrots in a steamer basket and place in the inner pot (directly if your basket has feet and on a trivet if it doesn’t, as it needs to be above the water).
Press Pressure Cook / Pressure / Manual (this will depend on your cooker) and programme 10 minutes, high pressure.
Quick pressure release (this means venting the steam trapped inside once the pressure cooking countdown finishes. It will be super light and fluffy and ready for mashing.
Mash with 50 g unsalted butter, black pepper and sea salt to taste. I purée it in my Thermomix, 50 seconds at speed 9 for a light and fluffy purée.