Julienne is a French cooking term for thin matchstick-like strips of vegetables, fruit, meat, or cheese. The strips are usually about 3 inches long and 1/16- to 1/8-inch thick. To make them, follow these steps:
Stand an apple on its base. Using a chef's knife, cut downward along the core, removing about a third of the apple. Repeat on the other side. You’ll be left with an apple disc that has the core in the middle.
Lay the disc flat. Cut away the usable apple on both sides of the core. Discard the core.
Take the pieces you’ve cut. Place them on the cutting board with the flat side down and the skin side up. With a chef’s knife, cut lengthwise into uniform thin slices about 1/16 inch thick.
Stack a few of these thin slabs and cut lengthwise into 1/16-inch-thick strips (the same width as the slabs).
Trim off the rounded edges of the larger pieces from step 1, making rectangles. Repeat steps 3 and 4.