Heat cream, butter, salt pepper in a pan. Make sure all the steam has gone from your drained potatoes. Mash in the pan over a very low heat. Then beat with a wooden spoon. Use a ricer for 100% lump free.
Never use a blender, it will release too much starch and create wallpaper paste.
It depends on what you're doing with it (just eating it, pie topping, will it go in the oven, etc) and also how you feel; sometimes I just hand-mash mine to a nice texture, other times I want it creamy.
Actually the most tasty mash ( for me if I have the time ) is to bake up some pots, scoop the innards out into a bowl and add a lil dash of salt n pepper and butter and gently stir with a fork. Exellent texture great colour and that baked pot taste..........perfect .