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Wild Mushroom Caramelized Onion and Kale Soup

Wild mushroom caramelized onion and kale soup is built on deeply golden onions, then simmered with mixed mushrooms and porcini for a rich, mahogany broth. The kale wilts into the soup right at the end, creating a hearty texture that’s finished with thyme and optional truffle oil.
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Prep Time 20 minutes
Cook Time 50 minutes
Total Time 1 hour 10 minutes
Servings: 6 servings
Course: Main Dish
Cuisine: American
Calories: 420
Ingredients Equipment Method Notes

Ingredients
  

mixed wild mushrooms (shiitake, cremini, oyster)
  • 1 lb mixed wild mushrooms (shiitake, cremini, oyster) Slice before cooking.
dried porcini mushrooms
  • 1 oz dried porcini mushrooms Soak in hot water; reserve soaking liquid.
hot water
  • 2 cup hot water Use for soaking porcini.
onions
  • 3 onions Thinly sliced.
kale
  • 4 cup kale Stems removed and chopped.
garlic
  • 6 garlic Minced.
broth
  • 6 cup beef or vegetable broth Use beef or vegetable broth as desired.
dry sherry or white wine
  • 0.5 cup dry sherry or white wine For deglazing.
butter
  • 3 tbsp butter For caramelizing onions.
olive oil
  • 2 tbsp olive oil For caramelizing onions.
fresh thyme
  • 1 tbsp fresh thyme Fresh, chopped.
balsamic vinegar
  • 1 tbsp balsamic vinegar Adds depth to the broth.
Parmesan shavings
  • 1 Parmesan shavings For serving.
truffle oil
  • 1 truffle oil For serving; optional.
salt and pepper to taste
  • 0.25 salt and pepper to taste Season to taste during the final step.

Equipment

  • 1 Dutch oven

Method
 

Caramelize the onions
  1. Melt butter with olive oil in a large heavy pot over medium heat, then add the sliced onions. Cook for 35-40 minutes, stirring occasionally, until they turn deeply golden and caramelized.
Brown mushrooms and deglaze
  1. Add the minced garlic and sliced mixed mushrooms, then cook for 8 minutes, stirring once or twice, until the mushrooms are browned. Stir in the sherry and cook for 2 minutes, scraping up any browned bits from the bottom of the pot.
Simmer with porcini and broth
  1. Drain the soaked dried porcini, reserving the soaking liquid, then add the porcini and the strained soaking liquid to the pot. Pour in the broth, then add fresh thyme and balsamic vinegar; simmer for 15 minutes.
Wilt kale and finish
  1. Add the chopped kale, then simmer for 5 minutes until wilted and tender. Season with salt and pepper, then top each serving with Parmesan shavings and a drizzle of truffle oil.

Notes

Pro tip: let the onions cook undisturbed for a few minutes at a time, then stir—this helps them reach true deep golden caramel color. Store leftovers in the refrigerator up to 4 days; reheat gently and add a splash of broth if needed. Freezing is yes, but kale may soften further; for best texture, under-simmer kale slightly and add fresh kale when reheating. For a vegetarian option, use vegetable broth and swap butter for plant-based butter if desired.