Step 1: Prepare the Potatoes: Begin by placing the peeled and cut potatoes into a pot of cold water. Bring the water to a boil, then reduce to a simmer. Cook the potatoes until fork-tender, about 15-20 minutes. Drain the potatoes and let them cool slightly.
Step 2: Mash the Potatoes: Using a potato masher, mash the cooked potatoes in a large bowl until smooth and free of lumps. Allow the mashed potatoes to cool completely before proceeding to the next step.
Step 3: Mix the Ingredients: Once the potatoes are cool, add the softened butter, heavy cream, sugar, and salt to the bowl. Mix until well combined. Gradually add the all-purpose flour, mixing until a soft dough forms.
Step 4: Chill the Dough: Cover the bowl with plastic wrap or a clean kitchen towel and place it in the refrigerator for at least 30 minutes.
Step 5: Roll Out the Dough: Once chilled, divide the dough into smaller portions for easier handling. On a lightly floured surface, roll out each portion into a thin round, approximately 1/8 inch thick.
Step 6: Cook the Lefse: Preheat a griddle or frying pan over medium heat. Carefully transfer the rolled-out dough to the hot surface. Cook for about 1-2 minutes on each side, or until lightly browned and cooked through.
Step 7: Store the Lefse: Continue the process with the remaining dough, stacking the cooked Lefse on top of each other and covering them with a clean kitchen towel to keep them warm and soft.