Through much of the country, this is the time of year when winter digs itself in and says, “Hello—no, I’m not going anywhere.” For many of us, the desire for lighter, healthier eating is an immediate cold-weather casualty, crushed by the teeth-chattering urge for a bowl of something hearty, warm, and satisfying.

Time to reach for Love Soup.

If you came of age on the hippie side of the 1970s, you may recall Anna Thomas’s first cookbook, The Vegetarian Epicure. Back then it was a revelation, a crucial shift in thinking that unfurled myriad possibilities. Meat, it turned out, wasn’t the center of the culinary universe, and Thomas was the Galileo who proclaimed the new, veg-centric order.

Browsing The Vegetarian Epicure today, what’s perhaps most striking is the sheer quantities of butter, cream, eggs, and cheese the recipes require. Vegetarian they may be, and delicious too, but no one cooks that way anymore—not even Anna Thomas.

Now in her 60s, an award-winning screenwriter and the mother of two grown (vegan) sons, Thomas brings a much lighter hand to Love Soup (W. W. Norton & Company, $22.95). The recipes are still vegetarian and every bit as satisfying, but their flavor springs from healthier sources: a drizzle of fruity olive oil rather than a dollop of sour cream, slow-caramelized onions instead of cheddar cheese.

Anna Thomas. Photo: Bruce Botnick, Boston Globe

Thomas has a locavore’s eye for the seasons, and the book is organized accordingly, moving from an assortment of bountiful autumn soups to soul-reviving winter stews, delicate and earthy tributes to spring, and sweet, hearty, and cold soups for summer. Among my favorite sections are the ones on “green soups”—tasty, vitamin-packed concoctions of kale, chard, spinach, and herbs paired with everything from sweet potatoes to portobello mushrooms—and winter squash soups, which conjure unsuspected richness from the most mild-mannered butternut or kabocha.

Along the way, Thomas adds sample menus built around specific soups, and the book’s final section offers a selection of breads, spreads, salads, and desserts that can turn any potful into a meal. Although the first chapter outlines various vegetarian broths, Thomas is no stickler on this—if there’s a commercially prepared one that you like, it’s fine with her. Vegan soups are conveniently indicated in the table of contents, and there are plenty of them to choose from.

The recipes are simple enough for entry-level cooks, but lend themselves to the kind of variation and embellishment that experienced chefs love to play with. Thomas’s touch with seasonings is admirably assertive but not overpowering—if an extravagant amount of thyme is called for, then that’s what that soup really needs. She has a deft way of explaining things without excluding novices, and her writing is graceful, welcoming, and eminently readable. Not surprisingly, Love Soup was a 2010 James Beard Foundation Book of the Year winner.

As I write, there’s snow outside and “Green Soup with Sweet Potatoes and Sage” simmering on the stove. As each bowlful leaves the pot, I’ll add the touch of olive oil that Thomas finds utterly essential for finishing this dish. (I couldn’t agree with her more.) In place of the squeeze of lemon she suggests, I might try a dab of chipotle salsa. I’ll serve the soup with a crusty bread and garlicky hummus, and the winter night will gradually take on a sweet-potato glow. What’s more, there’ll be plenty left for the rest of the week, the flavors deepening as they continue to meld in the fridge. What more could one ask from a cookbook? “More soups,” you might say. “And maybe some popovers, or a white-bean-and-roasted-tomato spread.” With Love Soup, Anna Thomas graciously obliges.