Mock Capers
Take green nasturtium seeds when they are full grown, but not yellow; dry for a day in the sun; put in jars and cover with boiling vinegar, spiced, and when cool cork closely. Fit for use in six weeks.
A one-paragraph pickle that depends almost entirely on picking the seeds at the right moment. Everything else is a vinegar pour and patience.
- The hinge: seed maturityNasturtium pods want to be plump, firm and still bright green, gathered a few days after the flower drops. Once they pale toward yellow or straw they turn woody and mealy, and no amount of soaking in vinegar will fix the texture.
- What "spiced vinegar" means hereThe book does not say which vinegar or which spices. Period pickling vinegars were generally simmered briefly with whole spices such as peppercorns, mace or bay. Use a vinegar labelled 5 percent acidity and do not dilute it with water.
- An overnight brine is worth addingA number of period recipes for pickled nasturtium pods include a salt step that this one skips: soak the pods 24 hours in a brine of about 2 tablespoons salt per cup of water, then drain and dry. It firms the seeds and draws out some of the raw peppery bite.
- "Dry for a day in the sun"The point is surface dryness, not dehydration, so the pods do not water down the vinegar. A day spread on a towel or a rack indoors does the same job.
- Jars and "cork closely"Corked stoneware and glass jars were sealed with a cork and often a wax or bladder cover. Use small glass jars with vinegar-proof lids, and keep them in the refrigerator rather than trusting a room-temperature seal; these are refrigerator pickles, not canned goods.
- Pour hot, cover completelyThe vinegar goes on boiling, and the seeds must stay fully submerged. Any pod riding above the surface will discolour and soften.
- Six weeks is realThe waiting period is not padding. Freshly covered seeds taste sharply of raw mustard oil; the weeks of standing round them into something more caper-like. Keep them refrigerated.
- Yield and useUse and substitution -- Use them as you would capers, in tartare and remoulade, with brown butter on fish, or chopped into a mutton or lamb sauce. They are hotter than true capers, so use a lighter hand at first.
True capers are the unopened flower buds of Capparis spinosa, a Mediterranean shrub that will not survive a northern winter, so English and American cooks looked for substitutes they could grow in the kitchen garden. Nasturtium (Tropaeolum majus), a South American plant that reached European gardens by the seventeenth century (the smaller T. minus somewhat earlier), was a favourite: its green seed pods carry the same mustard-oil pungency as the leaves and flowers, and pickled in spiced vinegar they take on a comparable brine-and-bite character. Recipes for them appear in English household books well before 1800 and were still familiar in American home cookery when this book was compiled. Broom buds, elder buds and unripe green grapes were pickled as mock capers on the same principle.