Melt the butter in a large heavy-bottomed pan over a low-medium heat. Add the sliced onion and a good pinch of salt and cook gently for 30-35 minutes, stirring regularly and reducing the heat if anything begins to catch, until the onion is soft and beginning to caramelise. Add the sugar and Worcestershire sauce and continue to cook for a further 5-10 minutes, or until the onion is lovely and sticky.

Combine the cream cheese, soured cream, crème fraîche, a good pinch of salt and few grinds of black pepper in a mixing bowl. Give them a good whisk, until smooth. Stir through most of the caramelised onion (I like to save a few spoonfuls for the topping) to combine, then taste and adjust the seasoning, if needed. Cover and refrigerate for a few hours, to help the flavour develop.

To serve, bring the dip back to room temperature and topped with the remaining caramelised onions and a handful of chopped chives. I like it with some warm baguette, but its very good with crisps or crudite, too.