Rondelles, bias slices and the roll cut

Three ways to cut long vegetables — straight across, at an angle, and with a turn — and when to use each.

Long round vegetables — carrots, zucchini, cucumbers, parsnips, leeks, daikon — are easiest to cut across the axis. The angle of the cut decides the shape of the piece and how fast it cooks.

Rondelles

Cuts across the axis. Thick vegetables are first halved or quartered lengthwise.

Thickness ranges from 3 mm to 1 cm: thin rounds for salads and quick frying, thick ones for soups and braises.
Halve or quarter a wide vegetable (a big zucchini, an eggplant) lengthwise first: you get half-moons and quarters that sit steady.
Onion rings are simply rondelles of a whole onion, and sliced garlic or mushrooms are the same thin 1–3 mm slicing.

Bias slices

The same vegetable, but the knife sits at 30–45° to the axis.

An oval slice has a larger cut surface: it cooks faster, holds more sauce and looks more festive.
A stir-fry classic: carrots, celery, asparagus, scallions and leeks; a baguette for croutons is cut the same way.
The sharper the angle, the longer the oval. Keep the angle constant and the pieces will match.

Roll cut

Cut at 45°, a quarter turn, cut again at the same angle — pieces with two angled faces.

Cut off the tip at a ≈45° angle.
Roll the vegetable a quarter turn (90°) around its axis.
Cut again at the same angle, 2–3 cm further along. Repeat: cut, turn, cut.
Where the vegetable gets thinner (the tip of a carrot), make the pieces longer: their volume stays about the same and everything is done at once.

The roll cut gives large pieces with several faces: they do not stick together, brown evenly and hold their shape in stews, roasting and wok cooking.

A long round vegetable rolls: hold it with a claw, and do not cut the last 2–3 cm in the air — lay the stub on its cut face or save it for stock.