When I talked to Wilkins about swapping ground spices for whole ones, his recommendation was to scale down the measurement to one-third the amount called for; and he says that "generally the same goes for cooking with dried herbs instead of fresh." That means if a recipe calls for 1 tablespoon chopped fresh rosemary, you should use about 1 teaspoon dried (since 1 tablespoon is equal to 3 teaspoons). The reverse also applies: if a recipe calls for 1 teaspoon dried rosemary, you can substitute 1 tablespoon fresh rosemary instead.
Your timing should vary, too: Add fresh herbs near the end of cooking, rather than at the early stages when you'd add dried herbs. For garnishing, add fresh tender herbs off heat; in a slow-cooked braise, add rosemary, oregano, or other sturdy fresh herbs about 30 minutes to 1 hour before the braise is done, but not earlier, since fresh herbs can turn bitter if cooked for too long.
Wilkins says that not all herbs follow his rules: "Some herbs like thyme, tarragon and basil dry quite well; others like cilantro and parsley add a nice color, but don’t pack much flavor punch," he says. In those cases, he says, fresh is best. (And frozen might be the best backup move.)
Perhaps most importantly, Wilkins notes "it helps to become familiar with each of the dried herbs in your cabinet for best results." Smell them and taste them when you're first opening the container. And then read his advice on a few of the herbs we use most often below.
Basil
"Sweet domestic basil loses some of its complexity and kick when dried—Egyptian dried basil is more assertive and works very well for dishes with longer cooking times. If using dried sweet basil, add it at the end of cooking so that the flavor remains vibrant."
Bay Leaves
"At the Spice House, we recommend cooking with dried Turkish bay leaves for their complexity and nuance. Fresh “California” bay leaves are available on the market but are not a good substitution because of their strong medicinal flavor."
Dill
"The flavor of dill is diminished when drying, but the color is very good," says Wilkins. That means you can scale up the one-third rule to one-half, or even higher. (Meaning: if your recipe calls for a tablespoon of fresh dill, start with ½ tablespoon dried.) It's worth remembering that when you're using dried herbs, especially in something like a cold sauce or dip, the flavor will need time to develop, so mix the sauce together and store it in the fridge for an hour before you plan to use it.
Chives
"Freeze-dried chives maintain a sweet oniony profile and a bright green color," says Wilkins. Use them as a garnish for baked potatoes, casseroles, and soups; or stir into dips, sauces, and dressings.
Cilantro
"The flavor of cilantro is greatly diminished when it's dried," says Wilkins. For that reason he recommends using fresh cilantro whenever possible. Before yours goes bad, consider making a green sauce to freeze!
Lemongrass
"Dried lemongrass stalk is very assertive," says Wilkins. The stems are also tough and won't really soften up. For that reason, he recommends breaking up the dried stalk (1 dried stalk = 1 fresh stalk) and dropping it into "a muslin bag for easy removal" once the dish is finished cooking. This also means you'll only want to use lemongrass in a recipe with plenty of liquid so the flavor can infuse.
