Zucchini, Fennel, Mint + Basil Soup

INGREDIENTS

2 tablespoons extra-virgin olive oil
1 small or medium fennel bulb, trimmed, thickly sliced, fronds reserved 
1 medium onion, finely chopped
1 garlic clove, finely chopped
1 pound, about 3, zucchini (courgettes), thickly sliced
2 handfuls basil
2 handfuls mint
1 liter vegetarian broth or chicken bone broth, or store-broth stock
1 1/2 tablespoons freshly squeezed lemon juice, plus zest to serve 
sea salt
freshly ground black pepper, to taste
extra-virgin olive oil, to serve
dried chili flakes, to serve
sesame salt, to serve

For The Bone Broth
1 bunch spring onions (scallions), green part only, roughly chopped
2 carrots, halved crossways
2 celery sticks, halved crossways
2 tablespoons unpasteurized apple-cider vinegar
1 bunch parsley, leaves removed
10 thyme sprigs
1 rosemary stalk (optional)
8 black peppercorns
4 liters water
2 pounds and 3 ounces bones or 3 tablespoons white miso (for vegetarian broth) 

For The Sesame Salt
2 teaspoons coriander seeds
1/2 teaspoon dried chili flakes
1 teaspoon fennel seeds
1/2 cup white sesame seeds
2 teaspoons sea salt

DIRECTIONS

Heat the oil in a medium saucepan over a medium heat. Cook the fennel, onion and garlic until softened, about 3 minutes. Add the zucchini, basil, mint and reserved fennel fronds and stir to combine. Pour in the broth and bring the boil over a medium heat. Reduce to a gentle simmer. Cook for 5 minutes, or until the vegetables are tender.

Add the lemon juice and season with salt and pepper. Using a high-speed or hand-held blender, blend the soup until smooth. 

Served topped with a drizzle of extra-virgin olive oil, a sprinkle of lemon zest, some chili flakes, and sesame salts for a boost in flavor and antioxidants.  

To make the broth, put the vegetables, apple-cider vinegar, herbs and peppercorns in a large stockpot that can hold at least 5 liters water. Pour in the water and bring to boil. Reduce to a low heat, add the bones (or miso if you're making vegetarian broth), and simmer according to the cooking instructions below:

vegetarian: 1 hour
fish: 8-12 hours
chicken: 12-24 hours
beef and lamb bones: 24-48 hours

Skim the surface occasionally to remove impurities and excess fat. The broth can also be prepared in a slow cooker. 

Strain the broth through a sieve lined with a large coffee filter. If your broth contains a lot of fat, refrigerate overnight to allow the fat to set in a layer on the surface. The following day, scoop out the fat. At this stage, the broth will look like jelly, but once heated, it will become liquid again. Store in the refrigerator for up to 5 days or freeze in 1 cup portions for up to 3 months. 

To make the sesame salt, toast all ingredients in a medium frying pan over a low heat for 10 minutes, or until golden and fragrant. Stir occasionally to ensure the seeds do not burn. Set aside to cool. Coarsely grind using a mortar and pestle, spice grinder or food processor.