Nut oils come in two varieties: toasted and untoasted. The toasted versions are one of a pantry’s best-kept secrets. They add a rich, roasted flavor to salads, meats, and even vegetables, drizzled on while still hot. They are quite delicate, so use them as you would toasted sesame oil-at most just a few moments over the heat, lest they volatilize and lose all their aromatic richness. Toasted nut oils can go rancid quite quickly. Always smell before using; they can be stored in the refrigerator for several months.

Testers’ Notes

Arugula can get awfully stemmy, particularly late in the fall. If you notice too many fibrous stems, cut them off-but make sure you use 4 cups packed leaves, even with the stems gone. And remember this: the smaller the arugula leaf, the less astringent the taste.

You can make the dressing up to 4 hours in advance. Store it, covered, at room temperature, and whisk it again before using.