Heat the oven to 240℃ (220℃ fan)/465℉. Put the pepper quarters, tomatoes, chilli, onion, two tablespoons of oil, a half-teaspoon of salt and plenty of pepper on a large oven tray lined with baking paper and toss to combine. Roast for 20 minutes, give everything a stir, then add the garlic cloves and roast for 15-20 minutes more, or until everything is softened and coloured.
Leave to cool, then peel the peppers and tomatoes, and discard the skins.
Transfer everything to a food processor, add the almonds, feta, half the ground toasted spices, two tablespoons more of oil, a quarter-teaspoon of salt and a good grind of pepper, and blitz smooth. Refrigerate to cool completely (and set slightly).
Meanwhile, make the salsa. Using a small, sharp knife, trim the top and tail off the lemon. Cut down along its round curves, removing the skin and white pith as you go. Release the segments from the lemon by slicing between the membranes, then roughly chop each segment in two or three pieces.
Put these in a bowl with the olives, coriander, the remaining two tablespoons of oil and the remaining ground toasted spices, and mix to combine.
To serve, spread the dip on to a wide, shallow plate and spoon the salsa into the centre.