In a 4-quart stockpot, bring 8 cups water to a boil over medium heat. Add potatoes and salt; cook until potatoes are tender when pierced with a fork, 15 to 20 minutes.
In a small saucepan, heat cream and butter over medium heat until butter melts. Set aside, and keep warm.
Drain potatoes. Transfer to a large heatproof bowl. Using a hand blender or a potato masher, combine cream mixture and potatoes until smooth. Cover with plastic wrap, pressing plastic wrap directly onto surface of potatoes. Let cool completely before using.
Notes
Store potato mixture in an airtight container, and refrigerate for up to 2 days. Let come to room temperature before using.
Recipe by TeaTime Magazine at https://teatimemagazine.com/shepherds-pies/