In Season: Flavorful, slightly bitter escarole thrives in cool weather. It grows from fall through winter, and can be found year-round in most supermarkets. What to Look For: A head of escarole looks like curly lettuce and can be as small as a softball or as large as a soccer ball. Choose firmly packed heads with unblemished leaves. How to Store: Wrap escarole in paper towels and store in an unsealed plastic bag in the refrigerator for up to four days.
In Season: Radicchio's peak season lasts from January to April, although most specialty grocers carry it year-round.What to Look For: This member of the chicory family comes in several varieties, with two types being most widely available in the United States: Treviso and Verona. Treviso leaves are oblong with pointed ends and grow in small, tightly packed heads. Verona radicchio grows in loosely packed round heads similar in shape to butter lettuce. Both varieties have purple leaves with white ribs. Choose radicchio with crisp leaves and no brown spots. How to Store: Keep radicchio in a tightly sealed bag in the refrigerator for up to one week.
To ensure that the lasagna doesn't come out watery, it's important that the greens go in dry. Let all the water evaporate during cooking, and then blot the leaves with a paper towel if necessary after removing them from the saute pan.