English walnuts, the walnuts we see most often, originally came from Persia, and are now used all over the world in dishes both sweet and savory. A hard, thick shell protects the two halves of nut meat inside, which can be revealed using a nut cracker. Walnuts are also commonly sold out of their shell in whole pieces and chopped. Chopped nuts are often added to quick breads, cookies, and brownies, while bigger pieces are delicious candied or spiced to enjoy as a nibble with cocktails or to add to a salad. Black walnuts are native to America; they're more closely related to hickory nuts than to common English walnuts. Their flavor is strong, but in small amounts, they add exotic interest to cakes and cookies.
4 oz. walnut halves (about 1 cup) = 3/4 cup plus 2 Tbs. coarsely chopped and 1 cup finely chopped or ground
When choosing nuts in the shell, look for whole, clean shells with no blemishes, holes, or cracks. Pick up a nut and shake it. If you can hear the nut rattling freely in the shell it's old and dry. When choosing nuts out of the shell, look for plump, unbroken nutmeats. Avoid those that are discolored or shriveled.
A rancid nut can ruin an otherwise perfectly prepared dish, so always taste several nuts from the batch before you use them. Walnuts can be used right out of the shell or container, though they will have an even deeper flavor if toasted oven at 350°F for 8 to 10 minutes.
Walnuts in their shell will last for months in a cool, dry place. Store shelled nuts airtight in the fridge or freezer for up to 3 months.