Step 1 Separate chopped broccolini stems from florets. Place florets and 1 cup of the cauliflower in
a food processor and blend until mixture resembles rice; set aside.
Step 2 Combine broccolini stems and remaining cauliflower with potato, onions, garlic, thyme, vegie stock, skim milk and parmesan in a large saucepan. Add 3 cups boiling water; bring mixture to the boil, then simmer, uncovered, for 20 minutes, or until soup thickens slightly and vegies are tender.
Step 3 Remove saucepan from heat. Purée soup with a stick blender until smooth. Return saucepan
to medium heat. Add reserved broccolini-cauliflower mixture and simmer for 3 more minutes, or until soup is heated through.
Step 4 Top soup with grated parmesan and chopped walnuts, and serve.