Potato, asparagus and parmesan soup recipe

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By Ronna Welsh

This soup, with its juxtaposition of long-cooked leeks and tender-crisp asparagus, is bright and rich, and hearty but not heavy. The ginger-garlic-miso paste, along with loads of parmesan cheese, do the heavy lifting of turning plain water into a delicious broth. A quick-to-make mustard seed butter is stirred into the soup just before serving.

Some tips for preparing the soup: Salt the cut asparagus while the soup is cooking so that it is ready to absorb the hot broth when added. Cutting the asparagus at an angle exposes more surface area to the salt. You’ll do some grating for the soup, but don’t bother cleaning your grater between ingredients. Everything goes in the same pot.

Prepare in advance: Prepare the soup until the potatoes are completely cooked, then refrigerate for up to 4 days. When ready to serve, reheat the soup, then add the rest of the ingredients.

Storage: Refrigerate up to 4 days.

From Ronna Welsh, cookbook author and founder of Brooklyn-based Purple Kale Kitchenworks.


Measuring cup

Servings: 4 (just makes 8 cups)

For the mustard seed butter

For the soup


Time icon

Active: 25 mins|

Total: 40 minutes

  1. Step 1

    Make the mustard seed butter: In a large saucepan over medium heat, toast the mustard seeds until they begin to release their aroma, shaking the pan a few times, about 1 minute. Reduce the heat to low and add the 2 tablespoons of butter. Cover and cook until butter melts and begins to sizzle, about 2 minutes. Transfer to a heatproof bowl, scraping the sides of the pot to get all the mustard seeds. Stir in a pinch of salt and set aside.

  2. 2nd step

    Prepare the soup: Return the pot to medium-low heat and add the 4 tablespoons of butter, ginger, garlic and miso. Cook, stirring constantly, until the mixture turns to a golden paste, 2 to 3 minutes. It may stick to the bottom of the pan – it’s good hot – but adjust the heat if it starts to burn.

  3. Step 3

    Add the wine, scraping up the bottom of the pan and reducing until the mixture coats the back of a spoon, about 2 minutes.

  4. Step 4

    Add leeks, reduce heat to low, cover and cook, stirring occasionally, until leeks are tender, about 4 minutes.

  5. Step 5

    Add the potatoes, water and 1 teaspoon of salt. Cover, increase heat to high and bring to a boil. Reduce the heat to bring the soup to a simmer and cook until the potatoes are very tender, about 15 minutes.

  6. Step 6

    While the soup simmers, in a medium bowl, toss the asparagus with the remaining 1/4 tsp salt; put aside.

  7. Step 7

    Once the potatoes are cooked, turn off the heat. Add asparagus and parmesan and mix well. Let the soup stand in the pot to melt the cheese and lightly cook the asparagus, about 1 minute.

  8. Step 8

    To serve, ladle the soup into individual bowls. Stir in the mustard seed butter, then add 1/4 tsp butter, a squeeze of lemon, and sprinkle fresh herbs to each bowl.

Nutrition information

Per serving (2 cups of soup)

  • calories


  • Carbohydrates


  • Cholesterol


  • Fat


  • Fiber


  • Protein


  • Saturated fat


  • Sodium


  • Sugar


This analysis is an estimate based on the available ingredients and this preparation. It should not replace the advice of a dietitian or nutritionist.

From Ronna Welsh, cookbook author and founder of Brooklyn-based Purple Kale Kitchenworks.

Tested by Anne Maloney.

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