Prepare Potatoes: Start by peeling and chopping medium yellow potatoes into small chunks.
Boil Potatoes: Toss the chopped potatoes into a pot of salted boiling water (add 1 teaspoon salt). Boil for 15-20 minutes until tender.
Mash Potatoes: Once tender, drain the hot potatoes and mash them until finely smooth.
Mix Ingredients: In a mixing bowl, add the mashed potatoes, sharp cheddar cheese, and cornstarch. Mix thoroughly.
Form Dough: Divide the mixture in half, place in bags and flatten.
Freeze Dough: Place the bags in the freezer for about 20 minutes.
Cut Strips: Cut the seams of the bags and slice the dough into strips.
Freeze Strips: Return cut potato strips to the freezer for another 20 minutes.
Fry: Heat vegetable oil to 350°F and fry the strips for 3-4 minutes.
Serve: Transfer fried sticks onto a wire rack to cool and serve hot.