Hearty Mexican Vegetable Soup: Begin with Leftovers, Reduce Food Waste

Tuesday, January 27, 2015

In the words of the famous chef James Beard, “It is true thrift to use the best ingredients available and to waste nothing.”

Mexican Cauliflower SoupSounds like my kitchen, where I often start with farm-fresh, local ingredients and global spices to bring you delicious dishes. Using leftovers creatively and employing parts of the plant you might otherwise overlook to reduce food waste are considerations, too. Not to mention it just makes good sense to use every part of the vegetable you can to stretch your food dollar. It’s also efficient: I’ve said it before and I’ll remind you again that I do not cook every day, because I, like you, get super busy with life. Indeed, the more I write, teach, speak, and talk about food, the less I actually cook. And when I do take the time, I often eat the same thing several days in a row, happily—and usually end up playing with leftovers around day three to make something new.

Today’s recipe showcases all of these themes by starting with leftover Mexican cauliflower, (or even just roasted cauliflower, really). Simply sauté a few additional vegetables for your soup base, toss in your chopped cauliflower greens and stems—parts that most people toss but are perfectly edible—and add some stock, beans, and seasonings.

The result is this satisfying vegetable soup, redolent with warm and spicy Mexican flavors, chunks of cauliflower and peppers bobbing in a super savory broth.

Dinner is served.

Hearty Mexican Vegetable Soup


  • 1/4 cup canola oil
  • 1 medium onion, chopped
  • 1/2 green bell pepper, chopped
  • 1/2 red bell pepper
  • 1 poblano pepper, chopped
  • 1 chipotle pepper in adobo, chopped (omit if you don’t like heat)
  • 2 tablespoons adobo sauce (as above)
  • 1 teaspoon sea salt
  • 1/4 teaspoon black pepper, freshly ground
  • 3 teaspoons cumin
  • 1 teaspoon chili powder
  • 1 teaspoon oregano
  • 1/8 teaspoon cayenne pepper (optional, to taste)
  • 4 cloves garlic, minced
  • 6 cups of cauliflower cores and leaves
  • 1/2 cup white wine (or beer)
  • 6-8 cups vegetable stock, preferably homemade, or no-salt broth or bouillion
  • 4 cups leftover Mexican cauliflower
  • 1 cup diced tomatoes
  • 1 cup pinto beans
  • Juice from 1 lime, freshly squeezed
  • 2/3 cup chopped cilantro
  • Drizzle or two of agave nectar (optional)


1. Heat oil in a large soup pot over medium, add onions and peppers, and season with salt and pepper. Sauté until cooked, about 6 minutes, stirring occasionally. In the meantime, chop the cauliflower leaves and cores. (It’s fine if it isn’t 6 cups, I just happened to have that much from earlier cauliflower dishes that I was saving for this purpose. Just use what you’ve got.)

Cauliflower Cores and Leaves

2. Once the onion-pepper mixture is cooked, stir in spices and garlic until fragrant, about 45 seconds, then add cauliflower stems and leaves. Stir over medium-low heat an additional 10 minutes, until stems have softened.

Mexican Vegetable Soup Base

3. Deglaze the pan with wine (or beer) and stir in 6 cups of the vegetable stock. Turn the heat to high, bring to a boil, and then lower the heat to simmer for 10 minutes to allow the flavors to come together.

Mexican Soup Broth

4. Add the leftover Mexican cauliflower, lime juice, tomatoes, beans, and cilantro.

Mexican Vegetable Soup | PK Newby

5. Stir to combine, then simmer a final 10 minutes or so to allow everything to come together. Add more stock to thin if desired. Taste and reseason with salt, pepper, and spices; you may want a touch of agave (for balance, not sweetness).

Mexican Vegetable Soup | PK Way

Cooking Options. You could omit all the extra veggies and just mix up your leftover cauliflower with broth and reseason, no problem. (I just like cooking, is all.) Alternatively, you could make this entire dish starting from basic roasted cauliflower and just add more of the other ingredients and spices to your liking.

This soup is incredibly satiating—cauliflower really fills you up!—and I enjoy this broth-based variation since my cauliflower-based soups are usually blended and creamy. You might actually call this a Mexican cauliflower soup, since cauliflower is the dominant vegetable, as you can see. Even so, I found the dish ends up taking on more of a hearty vegetable soup flavor by the time you add everything else.

Whatever you call it, make it to please your palate. I sometimes include frozen corn kernels to this soup, or add a carrot and celery when I’m sautéing the veggies; black or white beans may also show up. Add tomato paste for a richer, more tomato-ey flavor, or even purée some of it if that brings a smile to your face. Garnish with a bit of sour cream to add a touch of richness and mellow the spiciness. Or toss on a few corn chips for crunch (like I do for my tortilla soup). Or keep it simple and bright with a scatter of fresh cilantro, pictured below. As when making any soup, simply adjust the ingredients, seasonings, and garnishes in a way that makes you say “Mmmm…”

Hearty Mexican Soup | PK Newby

Because if dishes like this don’t inspire you to make planet-friendly food that helps you save money, reduce waste, conserve time, and get you and your kids eating more veggies, then what’s the point?


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Dr. P.K. Newby is a nutrition scientist, speaker, and author with expertise in all things food, farm to fork, whether preventing obesity and other chronic diseases through diet or teaching planet-conscious eating. As a health expert and food personality, she brings together her passions for food, cooking, science, and sustainability to educate and inspire, helping people eat their way towards better health, one delectable bite at a time. Healthy Hedonism (TM) is her philosophy: Because healthy food shouldn’t suck.

Copyright © 2011-2020 P.K. Newby. All Rights Reserved.

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