Line a baking sheet with parchment paper and add the walnuts. Broil in the oven for 5 minutes until slightly darker in color and fragrant, then set aside. Finely dice the onion and celery, slice the mushrooms, cut the carrot into ½ discs, cube the pumpkin, and mince the garlic.
Add the olive oil and butter to a stockpot over medium heat. Add the onions, carrots, and celery and saute for 3-5 minutes. Add the garlic and cook for 1 more minute.
Add the mushrooms and saute for 5 minutes. Add the pumpkin, bay leaf, paprika, crushed red pepper, black pepper, and chicken broth. Stir and bring to a simmer.
Reduce the heat to medium-low, cover and simmer for 10 minutes. Meanwhile, chop the walnuts until they become the size of rice. You can also pulse in a food processor; just ensure you don’t blend until too fine.
Add the walnuts to the pot and cook for 5-10 more minutes until the pumpkin is soft. Add the kale and heavy cream. Taste and season if needed.
Ladle the soup into bowls. Garnish with fresh herbs and serve!