Green is not a color you associate with winter cooking, which leans more to browns and tans. Still, though the salad days of the year may be behind us, don't give up on greens.
With cold weather's hardier greens, you actually get two vegetables in one. They're great in salads and they're also wonderful cooked.
The predominant winter greens are loosely grouped in the endive family: Belgian and curly leaf endive and radicchio.
In salads, these call for somewhat sturdier accompaniments than the simple oil and vinegar that will pass in summer. Dress Belgian endive with blue cheese and toasted walnuts and make a vinaigrette of walnut oil and sherry vinegar. Wilt the pale center leaves of curly endive in a hot bacon dressing and serve it with chopped hard-cooked egg. Because of its forthright bitterness, radicchio is best mixed with other forceful salad ingredients--arugula and shaved Parmesan cheese, for example.
What you might not expect is that all three lettuces can be cooked. In fact, you could argue they're even better that way. Belgian endive can be poached in a little chicken stock, then lightly covered with white sauce, bread crumbs and butter, and baked in a gratin. Use the tough outer leaves of curly endive in soups and stews; add it for the last 10 minutes of cooking so that it keeps its color. Radicchio is good grilled, but it also makes a sophisticated risotto. Shred it first, and it will melt into the rice as it cooks, infusing a rosy color as well as a hint of bitterness.
When you're shopping for these greens, make sure the outer leaves look fresh and vibrant--they shouldn't be wilted, faded or yellowed. Also check the bases--they should be moist, not dried out.
Belgian endive and radicchio are luxury ingredients. They are expensive because they take a lot of handwork to produce. Both are usually started in the field, then dug up and brought inside to finish.