To cut a fennel bulb, rinse it, cut off the stalks and feathery fronds just above the bulb, and trim a thin slice from the root end. Halve the bulb lengthwise through the root, cut the tough core out of each half, then slice it thin for salads or cut it into wedges for roasting and braising. Keep the stalks and fronds: they are edible too.
The fennel sold as a vegetable is Florence fennel, a selection of Foeniculum vulgare with a swollen, bulb-like stem base, sometimes called bulb fennel. Colorado State University’s nutrition center notes that the core of a big bulb may be tough, while smaller bulbs are more tender.
Prepare the bulb
Purdue Extension rinses fennel well in a cool stream of water, trims off the bottom and cuts the stems off the bulb, adding that the stalks and fronds can be used for cooking. Colorado State trims the root end slightly and peels off the outer layer of the bulb. University of Rhode Island’s nutrition education sheet rinses the fennel under cool running water to remove dirt before cutting.
Step by step
- Cut off the stalks. Lay the fennel on its side and cut the stalks off where they meet the bulb. Pull the fronds off the stalks and set both aside.
- Trim the base. Slice a thin piece off the root end, then stand the bulb on that flat base.
- Halve it. Cut the bulb in half lengthwise through the middle of the root, as Colorado State describes, and lay each half on its cut face.
- Remove the core. Colorado State and the University of Washington farm both cut the core out of each half; two angled cuts either side of it lift it out as a small wedge. Rhode Island’s method quarters the bulb first and removes the core from each quarter, which is easier on a large bulb.
- Slice or wedge. Slice each half thinly across or lengthwise for raw salads, or cut it into wedges for cooking. Purdue cuts wedges for braising and roasting, and notes that thin raw slices are easiest with a mandoline.
Cuts by dish
| Dish | Cut | Source example |
|---|---|---|
| Raw salads | Thin slices, core removed | Purdue: slice thinly; a mandoline makes it easiest |
| Roasting | Wedges, or ½-inch slices | Purdue wedges at 375°F; Rhode Island ½-inch slices at 400°F |
| Braising | Wedges | Purdue browns the wedges in butter |
| Garnish | Fronds, picked or chopped | University of Washington Farm: use them as a fresh herb |
If you use a mandoline, set it up and keep the food holder on the bulb as described in our guide on how to use a mandoline slicer.
Keep your fingers clear
A whole bulb is round and dense. Mississippi State Extension’s knife basics recommend cutting round food in half first, laying the flat side down, and tucking the fingertips of the guiding hand toward your palm. With the bulb halved and cored, every remaining cut starts from a flat face.
Storing fennel
Purdue suggests wrapping fennel loosely in a plastic bag and refrigerating it for up to 5 days; Rhode Island gives up to 10 days for the bulbs and 2 to 3 days for the greens. Purdue adds that the stalks and fronds freeze well, while freezing the bulb changes its texture because of its high water content.
The knife for this job
A gyuto or santoku handles the halving cut through the root, and slicing the halves is a job of straight board cuts that also suits a nakiri. If the blade binds, stop and reset the bulb rather than pushing harder or twisting the knife, as our guide on how to use a nakiri advises; gyuto vs santoku compares the two all-rounders. In our wa handle size guide, a 150–190mm santoku or nakiri takes the Mid-size handle and a 196–255mm gyuto the Chef size.
Sources: Purdue Extension FoodLink, fennel (rinsing, trimming, wedges, mandoline, roasting, storage, freezing); Colorado State University, Kendall Reagan Nutrition Center, It’s Fennel-ly Summer! (outer layer, halving through the root, core); University of Rhode Island Community Nutrition Education, Veggie Prep: Fennel (quartering and coring, roasting slices, storage); University of Washington Botanic Gardens, UW Farm: Focus on Fennel (core, fronds as herb); Wikipedia, Fennel (Florence fennel); Mississippi State University Extension, Kitchen Knife Basics (flat surface, curled fingertips).