Kentang Tumbuk Perancis Terbaik (Joël Robuchon)

Bahan-bahan (6 porsi)

• 2 lbs (1kg) russet potatoes (scrubbed but unpeeled)
• 1 tablespoon coarse salt
• 10 oz (280g) unsalted butter ((2 1/2 sticks), cut into cubes)
• 250 ml . whole milk
• 2 1/4 teaspoons salt
• 3 dashes ground white pepper