Preheat the oven to 400 degrees F (200 degrees C). Line an oven-safe skillet or baking pan with aluminum foil.

Poke potato skin all over with a knife; place in the prepared skillet.

Cook in the preheated oven until very tender and easily pierced with a knife, about 1 hour. Set aside until cool enough to handle but still very warm.

Scoop potato flesh into a bowl; mash with the back of a spatula until smooth and no lumps remain. (You can also use a potato ricer.) Add butter; stir until melted and combined. Stir in cream, salt, and sugar until smooth. Cover bowl; refrigerate until chilled, about 2 hours.

Stir in flour, in several additions, until dough can be kneaded by hand, adding enough flour to form a soft, but not too sticky, dough. You need to be able to roll it out fairly thin without it falling apart.

Wrap dough with plastic wrap; refrigerate until chilled, about 1 hour.

Divide dough into 8 portions. Dust each portion with flour and roll out on a well-floured kitchen towel to 1/8-inch thick, or thinner.

Heat a very lightly buttered nonstick skillet over medium-high heat. Add 1 lefse; cook, poking surface lightly with a fork, until golden brown blisters form, 2 to 3 minutes per side. Transfer to a plate; keep covered with a towel. Repeat with remaining lefse; stack onto plate. Serve warm.