70g unsalted butter
3 medium white-fleshed onions, roughly chopped
2 large cloves of garlic, finely chopped
1/2 tsp dried rosemary
1 tbsp white wine vinegar
3/4 tbsp caster sugar
1/2 tsp salt
4 tbsp double cream
2 tbsp milk
1 large long shallot, sliced
1 tsp rice flour or plain flour
sunflower oil, for deep frying
1 Melt the butter in large pan and then slowly sauté the onion and rosemary over a low heat for about 18-20 minutes, stirring often. Take care not to colour them, they should be translucent and totally, utterly tender.
2 Add in the garlic and cook for a further 2 minutes or so, then stir through the vinegar and sugar and cook until the vinegar has dissolved and the wet look to the onions has disappeared. Add the salt and transfer to a bowl to cool completely.
3 Place the onions in the bowl of a food processor or use a stick blender. Add the cream and milk and purée until thick, leaving a little texture and spoon into a serving bowl.
4 Toss the sliced shallot in the flour until well-coated. Pour a good inch of sunflower oil into a small saucepan and heat to 180C. Fry the shallots until a deep golden colour then drain on kitchen paper where they will crisp up. Sprinkle with salt, mix together then scatter over the onion dip.