Creamy White Bean Soup with Sage Gremolata

Name: Creamy White Bean Soup with Sage Gremolata
Prep time: 20 min
Cook time: 40 min
Total time: 1 h
Cuisine: American
Ingredients: 3 tablespoons olive oil; 1 large yellow onion, chopped; 5 cloves garlic, roughly chopped; 1/4 teaspoon red pepper flakes (optional); 2 cups low-sodium vegetables broth, plus more as needed; 3 (14-ounce) cans white beans, such as cannellini, including liquid (see recipe note); 1/2 teaspoon kosher salt, plus more to taste; 1/4 teaspoon freshly ground black pepper, plus more to taste; 35 fresh sage leaves (from about 5 sprigs); 1/2 cup loosely packed finely chopped fresh parsley; 1 clove garlic, minced; Finely grated zest of 1 medium lemon (about 1 tablespoon); 1/8 teaspoon kosher salt