1Peel and dice potatoes into even-sized chunks. Add to a large pot, pour in enough chicken stock to cover, add 1 tsp salt, and bring to a boil. Cook until knife-tender (approx. 12-15 mins). Drain and shake.
2Let potatoes steam for 1 minute. Add butter and milk to the pot and stir to melt the butter.
3Add potatoes to the pot and mash until smooth. Add Boursin cheese and continue mashing. Season with salt and pepper.
4Add to a serving dish, swirl the top, drizzle with melted butter, and sprinkle with chives and pepper.