There are three types of fennel – bitter fennel, the original wild form, sweet fennel, the one we use as a herb, and Florence fennel. The latter, which is used as a vegetable, is formed from the base of the leaf stems which swell into a succulent bulb just above the ground. The season begins in early winter and dominates the markets in Italy until the weather becomes warmer and the fennel bulbs begin to elongate and become stringy and hollow.
When choosing fennel bulbs look for firm, compact, completely spherical bulbs with young feathery shoots from the centre. The bulbs should be white and the tips of the swollen leaf base bright green. Fennel has a strong flavour and crisp texture. When eaten raw it is deliciously refreshing, with a hint of aniseed. When cooked, fennel becomes tender, sweet and soft, with a subtle flavour.
To prepare fennel for cooking, cut away the outer leaves that are stringy, and any stalks that are attached. Keep these to add to fish stock. Trim the bright green feathery bits, to add to dishes at the end.
Fennel seeds are gathered from wild varieties of fennel, which grow everywhere in Italy. They are used in the base of fish soups, pastas and risottos.