In a large pot, brown your diced onions, garlic and carrots on medium heat in some olive oil. In the meantime, bring your potatoes to a boil in a separate pot.
Once your potatoes are tender and done, add them to your pot containing the onions and carrots, and add along your broth, broccoli, cauliflower and some salt & pepper.
Let simmer for about 20-25 minutes on medium heat.
Transfer your soup mixture into a blender, and add your basil leaves, dill, greek yogurt, cheese and heavy cream.
Pour into bowls and serve with croutons.