Preheat the oven to 200°C (180°C fan-forced) and line a baking tray with baking paper. In a large, heavy-based saucepan, heat 1/4 cup (60 ml) of olive oil over medium heat. Add the roughly chopped onion, potatoes, garlic, and a pinch of salt. Cook for 3–4 minutes until the vegetables are slightly browned.

Add the chopped broccoli stems and florets to the pan. Cook for an additional 1–2 minutes. Pour in the stock and add enough water to fully cover the vegetables. Increase the heat and bring the mixture to a boil. Let it simmer for 15–20 minutes, or until the potatoes and broccoli stems are tender.

While the soup simmers, place the prosciutto slices on the lined baking tray. Sprinkle generously with parmesan and lightly drizzle with olive oil. Bake for 10 minutes or until the prosciutto is crisp and golden. Set aside to cool slightly.

Remove the soup from heat. Transfer the vegetables to a blender (or use a stick blender directly in the pot). Add fresh basil leaves and blitz until smooth. Adjust the consistency with additional soup liquid if needed and season to taste.

Ladle the hot soup into individual bowls. Top each serving with two prosciutto and parmesan crisps. Garnish with fresh basil leaves and extra parmesan if desired.