Turn on the oven at 180℃. Put the peppers in a large oven dish and put them in the oven for an hour.
Meanwhile, chop one red onion. Put some olive oil in a large heavy sauce pan and sauté the onions for a few minutes until glassy.
Add the coriander seeds, cumin seeds, smoked paprika powder and a tablespoon of lemon harissa. Give it a stir.
Then add two pressed cloves of garlic. Sauté for another minute.
Then add the polpa, give it a good stir and turn up the heat slightly to low-medium. Let it simmer while giving it an occasional extra stir.
Proceed to the next steps while the peppers are still in the oven.