Zero Waste Leek, Zucchini and Potato Soup

by Miche Genest

I made this soup with the foods I happened to have in the fridge that needed using up: half a zucchini, half a leek, mashed potatoes, a cup of 35% cream leftover from making caramel sauce and ground, dried rosemary left over from making duck rilettes. But this recipe is more a route than a trail, a rough guide rather than a precise, GIS-plotted path. Substitute whatever you’ve got going — wilted celery sticks, tired Swiss chard, roasted potatoes from last night’s dinner. At the end, jazz it up with a pinch of cayenne or a grating of nutmeg, or both.

Tip: The best way to wash leeks is to cut them in half lengthwise, slice thinly and soak in a bowl of cold water for 10 minutes. To drain, lift the sliced leeks from the water into a strainer or colander and shake off excess water before proceeding with the recipe.


  • 1 Tbsp (15 mL) olive oil*
  • 1 Tbsp (15 mL) butter
  • 1 leek, white part only (about 1½ cups or 350 mL) halved lengthwise, sliced, washed and shaken dry
  • Half a large zucchini, quartered and sliced (about 1½ cups or 350 mL)
  • 3 cloves garlic, minced
  • 1½ tsp (7.5 mL) dried rosemary (substitute thyme or dill — whatever!)
  • 2 cups (480 mL) chicken stock (aren’t you glad you saved those bones and made stock?)
  • 2 packed cups (480 mL) leftover mashed potatoes
  • 1 cup (250 mL) 35% cream (substitute milk or 10% cream or neutral rice milk*, whatever you’ve got)
  • Salt and pepper to taste*
  • A pinch of cayenne and a fresh grating of nutmeg*
* Not a local ingredient


  1. Heat oil and butter in a medium saucepan over medium heat.
  2. Stir in leek and sauté until softened, about 5 minutes.
  3. Add zucchini and cook for another 2 or 3 minutes, then stir in garlic and cook for another 2 minutes. Add whatever herbs you’re using.
  4. While the vegetables are cooking, heat the chicken stock in a small saucepan until it steams. Add stock to vegetables, cover, and bring to the boil.
  5. Reduce heat to medium low and whisk in mashed potatoes. Don’t worry if there are lumps. Simmer for 10 to 15 minutes.
  6. Remove from heat and blend with an immersion blender, or in a food processor, or press through a fine-meshed sieve.
  7. Return to the pot and to the heat, and whisk in cream or milk. Cover and bring to a low boil once more, whisking periodically. Add more milk or cream as necessary to thin the soup.
  8. Remove from heat, taste, add salt and pepper as necessary, and finish with cayenne and a fresh grating of nutmeg, if you like.
Makes about 6 cups, enough for 6 servings.