Broccoli, Cauliflower and Leek Soup

Ingredients

• 1 tbsp olive oil
• 2 medium white onions (diced)
• 2 stalks broccoli florets (with stalks, chopped into bite-sized pieces)
• 1 small head cauliflower (chopped into bite-sized pieces)
• 1 bunch leeks (chopped into large chunks)
• 1 large sweet potato (cubed)
• 4 cups vegetable broth (low sodium)
• 1 540ml can crushed tomatoes
• 1 540ml can diced tomatoes (low sodium)
• 1 large bag or container baby spinach
• Salt and pepper (to taste)