Take stalk of food waste: You can cook with stems and leaves, too

A book landed on my desk several weeks ago that led me to question my personal shopping habits. When it comes to buying fresh produce, sometimes I get a little obsessed. I land at the market or in the produce aisle and something strange happens to me. I get sucked in by the smells and how beautiful and fresh everything looks -- it’s almost as if I’m hypnotized. 

I start to think about all of the fabulous recipes I’ve flagged but have been too busy to try. I think about the juicer I haven’t used in months. Before I know it, I have a basket full of gorgeous vegetables, fruits and herbs. And what’s wrong with that?

While my intentions are always good, the problem is when that super-ambitious shopper gets home with the goods, life happens. Most of the recipes stay flagged, the juicer stays on the shelf, and too much of that gorgeous produce, or parts of it, sit ignored in the crisper. Then the guilt sets in as I fling those unrecognizable casualties into the compost pail.

It’s like Groundhog Day, because the next time I head to the market, it happens all over again.

I want to break the cycle. I want to use up what I buy. I want to stop wasting so much food.

I turned to award-winning San Francisco Chronicle food writer Tara Duggan, author of Root-to-Stalk Cooking: The Art of Using the Whole Vegetable. A graduate of the California Culinary Academy and the author of three previous cookbooks, Duggan is the recipient of a James Beard Foundation Journalism Award.

In the name of public safety (and so that no readers are killed as a result of reading this piece), it should be made clear that not every part of every plant is edible. When in doubt, check before you eat it.

Jennifer Russell: What prompted you to write a book on this subject?  

Tara Duggan (Clay McLachlan)

Tara Duggan: It all started with an article I wrote for the San Francisco Chronicle about local chefs who were focusing on vegetable parts that are usually thrown away. Chefs were even naming the vegetable “offal” on menus, just like they did when everyone was all excited about the nose-to-tail movement. For example, one chef was battering chard stems and serving them with aioli.

I was also spending a lot of time on vegetable farms with my brother and sister-in-law, who have a small organic farm in Mendocino, Calif., called Windy Hollow Farm. When you see the whole vegetable in the field, you notice all of the extra edible leaves that you rarely see in the supermarket, and you start getting excited about using them. I also got to see how much work goes into each plant, especially at Windy Hollow, which is completely solar-powered, organic and has very little access to water. This inspired me to want to make the most of vegetables I buy, whether at the farmers market, in a CSA basket or at the grocery store.

JR: The issue of food waste is huge and the statistics are staggering. Which produce tends to create the most waste? Do you have specific suggestions for us to start putting some of those extra parts to use?

Root-to-Stalk Cooking

TD: Food waste was a big impetus behind this book. Americans waste 40 percent of our food, mostly because we never get around to using it. According to a just-released study from Harvard Law School and the Natural Resources Defense Council, 22 percent of food waste comes from fruit and vegetables. Of the fruit and vegetables we buy, we discard 52 percent of them and only consume 48 percent. 

When it comes to specific produce, broccoli is a big waste producer since so many people throw out its edible stem and it’s so popular. Romaine lettuce is another -- if you get a whole head of it, you may toss out half of the dark green leaves, even though you can use them in soups or as wraps. I have a recipe where you use the leaves to wrap Korean bulgogi beef and rice, and another one where you simmer the dark green part in a soup with peas. Leeks aren’t as commonly used, but they also have a huge amount of dark green parts that most of us think of as inedible. They’re actually delicious but just take a bit longer to cook than the white and light green parts prized in so many recipes.

JR: In the book you talk about the anatomy of a vegetable. Can you break it down and explain how you organize the book around that concept?

TD: When I started learning more about vegetables, I began noticing how so many of them have similar parts. Once you’re aware of the parts, then you start thinking about how those parts can be prepared and eaten in similar ways. For example, beets have roots -- the beet itself -- plus they have leaves and stems. Beets have the same botanical name as Swiss chard, their leaves look and taste very similar, so you can substitute beet greens for chard in almost any recipe. Pretty soon you’ll start eating the leaves that come with your cauliflower and slicing up those crunchy broccoli stalks rather than composting them.

Anatomy of a Vegetable (Clay McLachlan)

JR: In addition to eliminating waste and saving some money, what might surprise people about the flavors inside of these various vegetable parts?

TD: The extra vegetable parts usually have the same flavor but one that is either slightly muted or a bit stronger than the main part, which makes them fun to play with in recipes. Beet leaves taste faintly of beets, which makes them perfect to add to a grain salad. I sauté them with garlic just like I would chard, then toss them into cooked barley or wheat berries with a dressing, and top the salad off with marinated roasted beets, creamy goat cheese and toasted walnuts. Other examples are radish leaves, which are peppery like radishes. I like to use them in a salad with a creamy dressing and add corn and tomatoes or other sweet vegetables to balance their flavor. 

JR: What are some of the more unusual or surprising parts that you've successfully incorporated into a dish or recipe -- those things most of us simply toss?

TD: I have found lots to love about chard stalks, such as how you can cook them until they are soft and then add them to a hummus-like dip in place of chickpeas. If you use red chard, the hummus will be a beautiful fuchsia color.

Fennel fronds and stalks are much sweeter than fennel bulbs. I like using them in braises and roasts, such as adding the stalks to the braising liquid in slow-cooked pork shoulder in place of celery, and stuffing the sliced stalks and fronds into the cavity of a whole roasted fish as a replacement for dill.

I also love to candy fennel stalks. First, you slice them thinly -- they are fibrous -- then dry them in the oven until they turn crisp and candy-like. They’re good as a snack, in yogurt or in a salad.

JR: Are there parts you found that simply weren't worth the effort to save or use?

TD: Definitely! A lot of my recipe tests fell on the cutting-room floor because the whole point is to help readers use up extra stuff. If it’s too much work, why go to the bother? For example, I thought making tomato skins into a powder was too much effort for the result. (You dehydrate the skins in the oven forever, then purée what’s left.) However, I’ve since learned you can do this with not just the skins, but also the cores, which might increase the volume enough to make it worthwhile, especially if you’re working with a lot of tomatoes such as in canning.

Some things just didn’t taste or look very good. For me, a recipe has to be delicious first and foremost. I tried doing something with basil stems, but they didn’t have much in the way of basil flavor. Even though some people swear by it for its medicinal value, dehydrated corn silk had no redeeming value for me -- which may not be such a shocking revelation.

JR: Do you have storage tips or things we should consider when saving parts to use later?

TD: The tops on root vegetables can leech moisture out of the vegetable, which is why you don’t see beet greens, radish leaves or carrot tops as often in supermarkets as you do at farmer’s markets, where everything is much fresher. Ideally, you should remove the tops when you get home and use them before you use the roots, since they are more perishable. Loosely wrap the tops in a damp paper towel inside a plastic bag for a day or two. Roots will last much longer.

JR: Do you have a favorite dish or method? Something that highlights the flavor virtues of these "cast-offs”?

TD: One of the dishes that most captures the idea of the book is a Leek Greens Stir-Fry with Salty Pork Belly, inspired by a Chinese restaurant in my neighborhood. You use only the dark green part of the leeks, preferably leftover from another recipe (they actually last a while in the fridge). Trim, then slice them about 1/2 inch thick and stir-fry them with garlic, chiles and strips of salted pork until they become lightly charred and tender. At the end, you add a dash of soy sauce and a tiny bit of sugar. They taste like a cross between chives and spinach. 

Duggan's recipe: Leek Greens Stir-Fry with Salty Pork Belly