Scrub and dry the potato thoroughly. Prick all over with a fork.
Place the potato directly on the oven rack. Bake 60–75 minutes until completely tender when pierced.
Split the potato lengthwise. Scoop all the flesh into a bowl, keeping the skin intact.
Fold in warm butter, then cream. Season with salt and white pepper.
Mix until smooth, rich, and spoonable, not loose.
Spoon the mashed potato back into the skin.
Add a quenelle or generous dollop of crème fraîche.
Top with caviar.
Finish with chives and a tiny crack of white pepper.
Notes
Storage: best assembled and eaten right away. The baked potato and mashed filling keep covered in the fridge for up to 3 days; add crème fraîche, caviar, and chives fresh at serving.