Creamy Lemon and Herb Sauce

Pulverizing the herbs makes their flavor stronger, a good thing for a cold sauce where flavors can be muted.

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  1/2 cup (1/2 oz.) coarsely chopped fresh cilantro
  
  


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  1/2 cup (1/2 oz.) coarsely chopped fresh dill
  
  


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  3 whole scallions, sliced
  
  


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  1 tsp. finely grated lemon zest
  
  


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  Kosher salt and freshly ground black pepper
  
  


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  1/4 cup extra-virgin olive oil
  
  


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  1 tsp. fresh lemon juice; more as needed
  
  


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  8 oz. (1 cup) sour cream or crème fraÎche
  
  

Pulse the cilantro, dill, scallions, lemon zest, 1/2 tsp. salt, and 1/4 tsp. of pepper in a food processor until finely chopped. With the motor running, pour the olive oil and lemon juice through the feed tube and pulse until the mixture has a pesto-like consistency. Transfer to a small bowl and stir in the sour cream. Refrigerate for at least 1 hour to let the flavors meld. Season to taste with more salt, pepper, or lemon juice.