Rehydrate the Chillies: Place the de-seeded dried chillies in a heatproof bowl. Pour over enough boiling water to cover them completely. Let them sit and soften for about 20-30 minutes. Once they are pliable, drain them, but be sure to reserve about 100ml of the soaking water.

Toast the Spices: While the chillies are soaking, place the whole coriander, cumin, and caraway seeds in a small, dry frying pan over a medium-low heat. Toast them for 2-3 minutes, shaking the pan frequently. You'll know they're ready when they become incredibly fragrant and a shade or two darker. Be careful not to let them burn. I learned that the hard way once!

Grind the Spices: Tip the toasted spices into a spice grinder or a pestle and mortar and grind them to a fine powder. This step is crucial for unlocking the best flavour, as explained in this great guide on toasting spices.

Prepare for Blending: Place the softened, drained chillies into the bowl of a food processor or a high-powered blender. Add the freshly ground spices, peeled garlic cloves, smoked paprika, salt, lemon juice, and tomato purée.

Blend to a Paste: Pour in about half of the olive oil (around 60ml). Begin to blend the mixture, stopping to scrape down the sides as needed. What works best for me is to add the reserved chilli soaking water one tablespoon at a time until the paste reaches your desired consistency. It should be thick but spreadable.

Finish and Store: With the processor running, slowly drizzle in the remaining olive oil until it is fully incorporated and the paste is rich and glossy. Have a taste and adjust the seasoning if necessary, adding a little more salt or lemon juice. Transfer the harissa to a clean, sterilised jar. Pour a thin layer of extra virgin olive oil over the top to create a seal, which helps it last longer.