A slender-leaved herb with a sweet aniseed perfume from estragole, and a faint numbing quality on the tongue that no other common herb has.
What it does in a recipe: The defining aromatic of French sauce cookery — it perfumes cream, butter, vinegar and eggs without needing much heat. Pick the swap that covers that job — the ratios below are written so you can act on them without doing any arithmetic.
Chervil carries a gentler version of the same anise note and belongs to the same French fines herbes tradition, so it fits the same dishes at slightly higher volume.
MethodAdd it off the heat. Chervil is even more fragile than tarragon and collapses under sustained warmth.
Trade-offSofter and more delicate. A béarnaise will be pleasant but will lack the assertive perfume that defines it.
Cooking around an allergy? Diet tags here describe the ingredient itself, not any particular brand. Processed products change formulation without notice and shared production lines are common, so read the label on everything you use. A severe allergy is a medical matter — confirm with the manufacturer or your clinician rather than relying on a substitution chart.