If you're struggling to use up leftovers like a half-eaten rotisserie chicken, turn the assignment into a creative exercise, says chef Margaret Li. It'll make the cooking process more fun and less guilt-driven. Pulse/Getty Images/Corbis RF Stills hide caption

On a recent weeknight, I opened up my fridge and found an assortment of half-eaten or ignored food.

That included takeout that I didn't find appetizing enough to eat for lunch. A rotisserie chicken with most of the meat picked off. A couple of raw vegetables from the farmers market that were starting to wilt.

"There's nothing to eat," I told myself. Yet even I knew that was ridiculous. There was plenty of food in my fridge. I just didn't feel inspired to cook with it.

So I asked some chefs for guidance. How could I more consistently use leftovers and the other ingredients I tend to overlook?

Start with a mindset shift, says Margaret Li, chef and co-author of the cookbook Perfectly Good Food: A Totally Achievable Zero Waste Approach to Home Cooking. Think about cooking with leftovers as a creative, experimental exercise, not a guilt-driven one.

"It ends up being this fun game where you are creating something from what seems like nothing and solving this puzzle, and then you get to eat it," she says.

There are other good reasons to use up your food scraps. Nationally, about a quarter of food products go to waste, according to the nonprofit ReFED. In my own household, where we spend about $200 a week on groceries, that means I might be throwing out the equivalent of $50 of food — an unnecessary burden on my wallet, not to mention the environment.

The chefs I spoke to had some practical tips about using up more of the food we buy. Here are a few that I put to the test.

Build up an arsenal of go-to recipes that are flexible enough to use up just about any ingredient. Li calls them "hero recipes."

I tried one of these from her cookbook, called "Make-It-Your-Own Stir-Fry." (Scroll down for the recipe.) It includes loose ingredients like "1 pound crisp-crunchy vegetables" or "4 cups leafy greens."

In the spirit of the recipe, I pulled vegetables out of my fridge at random and did not measure them out. The sauce was a simple mixture of soy sauce, vinegar, sugar and water. By the time I topped my bowl with chopped scallions, the dish looked like a gourmet meal, not an afterthought.

Other ideas: "You could put anything in a frittata, and it'll be great," says Tamar Adler, chef and author of The Everlasting Meal Cookbook: Leftovers A-Z.

Or, if you have day-old rice on hand, cook it alongside other ingredients to make fried rice. "Saute some aromatics — ginger, garlic, onion — in oil," Adler says. Then add your rice and whatever leftover bits you have, like the rotisserie chicken and older produce I had in my fridge.

"Just take the approach of making it more flavorful and crispy and then spicy, and then usually adding a squeeze of lemon," Adler says.

Keep a permanent marker and painter's tape in your kitchen to label and date your leftovers, Li says.  "That is a classic chef's method for knowing what something is and when it was made. That saves you the guessing game."

Adler takes the concept a step further and labels her leftovers with their intended use. Leftover blueberries are labeled "muffins-to-be on Tuesday," she says. "I really like doing that — assigning the destiny of the food."

So after a night of Ethiopian takeout, when we ended up with an entire container of leftover injera, I followed Adler's advice and thought about what it might become in the future.

I imagined scrambling the spongy, tangy bread with eggs, akin to scrambling matzo into matzo brei. "Injera for eggs," I wrote on the container. Sure enough, their destiny was fulfilled the following morning.

Li keeps a dedicated bag in her freezer just for scraps from which to make chicken or vegetable stock. That bag houses carrot peels, the ends of onions, extra garlic cloves and chicken bones. Flavia Morlachetti/Getty Images/Moment RF hide caption

Adler encouraged me to never, ever throw away the stems of herbs. Stems don't get as much glory as tender, pretty leaves, but they still have the same herby taste.

"I'm going to chop these herbs up or stick them in a blender with a clove of garlic," she says. Then add olive oil. "And then it's just gonna be my base sauce for everything."

So I foraged a few varieties of half-cut herbs from my refrigerator drawers, most of them sad looking and unidentifiable.

I threw out the stems that had turned brown and gooey and put the rest in a blender. I added garlic on Adler's instructions, nuts and kale for bulk, and plenty of olive oil and salt. Then, on a whim, I added a splash of olive juice for brightness.

The result was somewhere between a pesto and a chimichurri, and it elevated that night's otherwise routine dinner. And Adler was right: Once the stems were blended, it tasted exactly the same as the leaves. (The same idea applies for broccoli stems in a cheesy broccoli soup, Li says.)

Li likes to keep her odds and ends organized with an "Eat Me First" box in her fridge. That's where she keeps half-used lemons, leftover coconut milk or produce that's starting to get wrinkly. "You kind of have an idea for, OK, here's where you look first," she says.

Cooking these meals did feel like a game, as Li had suggested. It brought me unexpected joy to use up as many existing ingredients as possible — to the point where I often spent much longer in the kitchen because I kept thinking of new ideas: If I turn these wrinkly sweet potatoes into a soup, then I can caramelize this half-cut onion for a topping, and then I can use the leftover soup as a sauce tomorrow ...

Did I cook more often, though? Probably not. My cooking energy burned brighter but fizzled out after a few nights, at which point I ordered takeout.

So I was glad to hear Li's take: If you're too hard on yourself, you're not going to enjoy it at all. " I try not to be too obsessive about eating absolutely everything," she says. If my takeout was truly terrible, I'm allowed to toss it or, better yet, compost it.

If you really want to use up everything, you can always chuck ingredients into the freezer. Li has dedicated freezer bags for different dishes, like vegetable scraps for soups or fruit discards for smoothies. (She labels them, of course.)

And how does that smoothie taste? It's "delicious," she says, "even if it's made up of all the things that have been rejected in the past," she says.

Excerpted from Perfectly Good Food: A Totally Achievable Zero Waste Approach to Home Cooking. Copyright ©2023 by Irene Li and Margaret Li. Used with permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.

Stir the sauce ingredients together in a small bowl and set by the stove.

Heat a wok or large skillet over high heat until just smoking, then add the neutral oil and tilt to coat the bottom of the pan.

Add the garlic, ginger (if using), and chili flakes (if using) and stir-fry for 10 seconds. Add the greens and/or vegetables, in stages as necessary, and toss in the garlicky oil, then add the sauce and cook to your liking, stirring frequently.

Vegetable chunks may need 4 to 7 minutes — if you want to speed up the process, cover the pot so the vegetables steam for a minute or two, then uncover and toss again. Sturdy greens may need 3 to 5 minutes to get tender (we like to let them sit for a bit and char for extra texture).

Lighter leaves will need less than a minute to wilt down. Stir in a spoonful of any additional sauce you like, season with salt to taste, then sprinkle with your favorite garnishes and a generous drizzle of sesame oil.

A sprinkle of crunch is a great way to finish a stir-fry. Our favorites include crushed cashews or peanuts, toasted sesame seeds, thinly sliced scallions, and fried onions or shallots.

We'd love to hear from you! Share your recipe with us at [email protected] with your full name. We may publish it on NPR.org.

The story was edited by Malaka Gharib. The visual editor is CJ Riculan. We'd love to hear from you. Leave us a voicemail at 202-216-9823, or email us at [email protected].