Harissa: Make this with leftover pesto, sundried tomato paste, tapenade, even some gochujang.

Frozen fish: Frozen fish works fine but it must be fully thawed. Continue as instructed in the recipe.

If you want to use dried beans: Use about 100g dried cannellini to make ~240g cooked (equivalent to one drained 400g tin). Always cook dried beans *separately* (soak + simmer) until just tender, then add to the stew during the simmer stage.

If you want to double the recipe: double everything and continue.

What to do with leftovers: Leftovers can be kept in an airtight container for 2 days in the fridge. If you need, I would reheat in the microwave for 1-2 minutes until hot all the way through. However, fish does not reheat well, and cod is one of the few fish that is not that great cold so ideally, I would just cook the amount of cod you need and eat that fresh. Then the tomatoes and beans make delicious leftovers. Making this recipe with prawns works well too, and those leftovers keep better and can be eaten cold.