Broccoli and Cashew Cream Soup

Name: Broccoli and Cashew Cream Soup
Ingredients: 1 cup raw cashews; 1 garlic clove, coarsely chopped; 1 Tbsp. extra-virgin olive oil; ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt; 2 medium heads of broccoli (about 1½ lb.); 2 Tbsp. extra-virgin olive oil; 1 leek, white and pale green parts only, thinly sliced; 4 garlic cloves, coarsely chopped; 2 tsp. fennel seeds; 4 cups low-sodium vegetable broth; 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt; ¼ cup tender dill sprigs, plus more for serving; Freshly ground black pepper