In a saucepan, combine 1 cup water (250 ml) and 1 cup whole milk (250 ml), a piece of butter, salt, and freshly ground pepper. Bring to a boil, remove from heat, add the instant mashed potatoes, stir, and let sit to cool. Set aside.

In a bowl, combine all the chopped ingredients and add mayonnaise. Mix well to make the filling for the roulade.

On a sheet of plastic wrap, spread out the mashed potatoes. Place the filling in the center, being careful to leave the edges clear so you can roll it up. Don’t overfill or it will be hard to roll.

Using the plastic wrap, carefully roll up the potato and filling into a log. Wrap tightly in the plastic wrap and refrigerate for at least 2 hours so it firms up and is easier to decorate.

After chilling, decorate as you like. I used mayonnaise, grated hard-boiled egg, anchovies, pickled white anchovies, cocktail sauce, romaine hearts, surimi, and pickled onions. Enjoy!