Green Soup with Ginger Recipe

INGREDIENTS

• 1 large yellow onion (250g)
• 2 tablespoons (30 ml.) olive oil
• 1 1/2 teaspoons sea salt, plus more to taste
• 1 large sweet potato (12 ounces; 350 g)
• 1 large leek, white and light green parts (5 ounces; 140 g)
• 1 bunch spinach (8 ounces; 225 g)
• 1 large bunch green chard (12 ounces; 350 g)
• 3 tablespoons (30 g) chopped fresh ginger, plus more to taste
• 2 cups (500 ml) good-tasting vegetable broth
• 2-4 teaspoons fresh lemon juice
• freshly ground black pepper