Fennel and White Bean Soup

Name: Fennel and White Bean Soup
Prep time: 10 min
Cook time: 35 min
Total time: 45 min
Cuisine: American
Ingredients: 1 large fennel bulb (chopped (reserve some fronds for garnish)); 1 small onion (diced); 2 cloves garlic (minced); 2 tbsp extra virgin olive oil (plus more for drizzling); 1 can white beans ((15 oz can)); 3 cups low-sodium vegetable broth; 1/2 tsp salt (or to taste); 1/4 tsp black pepper (or to taste); 1 tsp dried thyme (or 1 tbsp fresh); 1 pinch crushed red pepper flakes ((optional)); 2 tbsp lemon juice (freshly squeezed); 1 tsp lemon zest (for garnish)