Start by peeling and slicing the onions. If they make your eyes water, there are many homespun remedies for preventing or at least reducing the problem, one being to peel the onion and then soak it in water. You can also put the onion in the freezer for 15 minutes before slicing it.
Pour enough Extra Virgin Olive Oil from Spain into a frying pan to cover the base. The gorgeous golden colour is really impressive; it’s not surprising that it’s known as Spain’s liquid gold.
On a medium heat, add the onions and stir well so that everything is coated in oil.
Lower the heat a little and cover, leaving the onions to gently sauté. Stir occasionally to ensure even cooking.
Once the quantity has reduced by half, add two tablespoons of water and stir.
Almost immediately the onions will take on a creamier texture due to the water coming into contact with the sugars they released, dissolving to form a light caramel that gives that wonderful toasted colour to the marmalade. For an even deeper colour, add two tablespoons of cane sugar. Stir well to achieve an even colour. Add a pinch of salt to enhance the flavour, and the marmalade is ready.
Store in airtight glass jars that can be frozen or, if preferred, vacuum pack the marmalade.