Potato, cheese and salmon are a wonderful combination in this soufflé.
With buttery spread, grease four individual soufflé dishes (one cup capacity) and dust with flour. Set aside.
Cook potato in boiling water until tender; drain. Mash until very smooth. Transfer to a mixing bowl to cool. Beat in egg yolks. Add cheeses and salmon, mixing well. Season with salt and pepper.
Whisk the egg whites until they hold firm peaks. Fold into the potato mixture with a metal spoon until fully incorporated. Spoon the potato mixture into the prepared soufflé dishes.
Bake in preheated 425ºF oven for 30 minutes or until golden and set. Serve warm.