Cut the russet potatoes into 2-inch chunks for even, consistent cooking throughout. Place the cut potatoes in a large pot and cover them completely with cold water by about 1 inch—starting with cold water helps the potatoes cook evenly and prevents the outside from falling apart before the inside is tender. Add the salt to the water, which seasons the potatoes from within and also raises the water's boiling point slightly, helping achieve a better texture.

Bring the pot to a boil over high heat, then reduce to a gentle simmer and cook for 10–15 minutes until the potatoes are completely tender and a fork passes through them with no resistance. While the potatoes cook, you can prepare the butter and milk in the next step to maximize your time in the kitchen.

While the potatoes are simmering, cut the unsalted butter into smaller pieces and set it out to soften—this helps it blend seamlessly into the hot potatoes without overworking the mixture. Warm the milk to room temperature or slightly warm; cold milk will cool down your hot potatoes and can make them gluey, while room-temperature milk incorporates smoothly and creates a creamy texture. I like using Kerrygold butter because its rich, golden quality elevates the final flavor beyond standard butter.

When the potatoes are tender, drain them thoroughly in a colander, shaking gently to remove excess water. Return the drained potatoes to the hot pot and let them sit undisturbed for about 1 minute—this allows any remaining surface moisture to evaporate, which is crucial for achieving fluffy, light mashed potatoes rather than dense, wet ones.

Working with the hot potatoes, press them through a potato ricer directly into the pot, pressing firmly to create light, fluffy strands. Once all potatoes are riced, immediately add the softened butter from Step 3 and stir gently with a spatula or wooden spoon using a folding motion—this distributes the butter evenly without overworking the potatoes, which can make them gluey. Pour in the warmed milk gradually while stirring until you reach your desired consistency; I prefer creamy but still holding some shape, so I add milk slowly and stop when the texture feels right.

Taste the mashed potatoes and adjust the seasoning with white pepper and additional salt if needed. White pepper is preferred over black pepper here because it blends invisibly into the creamy white potatoes and provides a subtle heat without visible flecks, creating a refined, smooth appearance.