In saffron, vinegar and almond oil
You can find garum online, or follow Josh's method to make your own (you'll need a circulator bath).
To produce the garum, calculate the total weight of heads, bones and scraps you have from small fish such as sardines, mackerel, anchovies or gurnard (make sure that the gall bladder is removed as it will make the finished sauce extremely bitter). Measure 50% of that weight in water and add to the trimmings. Calculate 20% cent of the combined weight and add this quantity of fine salt.
Mix together, then transfer to a Mason (Kilner) jar, seal and place in a circulator bath set to 40°C (104°F). Leave for 7 days, stirring once a day.
Once it’s ready, store the garum in a sterilised Mason jar or airtight container in the fridge for up to a month.