Step 1

Heat olive oil and butter in a large saucepan over high heat, add leek, garlic and star anise and sauté until leek and garlic start to caramelise (3-5 minutes). Add fennel, thyme and bay leaf, and stir until fennel softens slightly (2-3 minutes). Add stock, season to taste, cover and bring to the boil, then remove lid and cook uncovered, stirring occasionally, until fennel is tender (10-12 minutes). Discard herbs and star anise, add crème fraîche, season to taste and blend with a hand-held blender until smooth.

Step 2

Meanwhile, for four spice, grind spices with a mortar and pestle.

Step 3

Scatter soup with fennel stalks and fronds, season to taste with four spice and serve with sourdough toast.