You're all signed up to velvet-textured spoonfuls when you make this classic soup. We're going extra premium on the creamy cauliflower and sweet leek combo here with a drizzle of nutty sage butter. Garlic bread is on-hand for mopping, because you won't want to leave anything behind in the bowl.
Preheat oven to 220°C fan-forced for garlic bread. Prepare garlic bread according to packet instructions. Cut green top from leek and discard. Halve leek lengthwise, rinse under cold water and finely slice. Zest lemon. Heat oil in a large saucepan over medium heat. Add leek, lemon zest and ¼ teaspoon salt and cook, stirring, for 4–5 minutes or until leek is very soft.
Peel and crush garlic. Add garlic to saucepan and mix to combine with leek. Cook for 30 seconds or until fragrant.
Peel and roughly chop potatoes. Roughly chop cauliflower. Add potato, cauliflower, stock cube and 1 litre (4 cups) water and bring to the boil. Reduce heat to medium and simmer for 20 minutes or until potato and cauliflower are very tender.
Juice lemon. Stir through lemon juice and parmesan.
Remove soup from heat and, using a hand-held blender, blend until smooth. Season with salt and pepper.
Melt butter in a small frypan over medium-high heat and cook for 2 minutes or until nutty brown in colour. Pick sage leaves and add to frypan. Cook for 15 seconds or until crisp. Remove from heat. Divide soup between bowls. Swirl through crème fraîche and top with sage leaves and butter. Serve with garlic bread.