Matchstick potatoes are potatoes cut into sizes the thickness of a matchstick (though usually longer), then fried, and served hot.
They are often served in mounds
There are also oven-baked versions now.
You need to use floury potatoes to have them turn out well.
You also really need a mandoline to make them.
You have to first peel the potatoes, and then trim them into rectangles or blocks.
Use a mandoline to cut them into sticks about 3/16 inch (5mm) thick, and as you cut them, set them in cold water.
Heat oil to 365 F (185 C.) Drain water off potato sticks on a paper towel (or even in a salad spinner.)
Lower the potato carefully in oil on slotted spoon; watch out for hot oil splattering.
Deep fry for 3 minutes (or less – watch carefully), until golden and crisp, then drain on paper towel.
You can keep them warm in an oven.