Sous vide mashed potatoes

Vacuum seal the potatoes with the butter, salt, white pepper and heavy cream.

Cook in a 194F sous vide bath, insulated with a clean kitchen towel if needed, 30 to 40 minutes, until crushable with gloved fingers.

Crush into manageable pieces and press through a fine mesh sieve with the cooking liquid.

Whisk minimally, just enough to incorporate the butter; smooth into a serving bowl.