To create the harissa paste, place your red peppers under the grill of your oven and grill until the skin begins to blacken. Remove the peppers from the oven and set them aside to cool down for 10 minutes, then remove the skin and seeds.
In the meantime, place the dried chilies into boiling water to soften for 10 minutes. Toast your caraway seeds in a small pan on the stove for 2-3 minutes whilst stirring.
Transfer the peppers, chilies, garlic, caraway seeds, tomato paste, ground coriander, cumin and smoked paprika powder, salt and lemon juice to a small food processor and blend for 1-2 minutes until the ingredients are broken down into a smooth sauce.