Step 1

Heat olive oil in a large saucepan over medium-low heat until shimmering. Add onion and a generous pinch of salt and cook, stirring occasionally, until the onion has softened but not taken on any colour, about 5-10 minutes.

Step 2

Add cumin, cinnamon, ginger, coriander, cardamom, cloves and chilli flakes. Cook, stirring constantly, until the spices have darkened and turned very fragrant, about 2 minutes.

Step 3

Add garlic and lemon zest and cook for another 30 seconds

Step 4

Add lentils, stir to combine in the onion and spices mixture, then pour over vegetable stock. Increase the heat to medium, bring to a boil, then reduce the heat to low and allow to simmer, uncovered, until the lentils are very tender and begin to break down, about 20 minutes.

Step 5

Once the lentils have cooked through, vigorously whisk the soup until it is slightly pureed, thickened and homogenous, about 30 seconds. Stir in the lemon juice, adjust for seasoning and serve.