1 egg yolk lightly beaten with a dash of milk for egg wash
Preheat oven to 130C fan-forced (150c non fan).
Cut each onion in half and thinly slice.
Place butter and olive oil in a heavy based pan on low heat add onion, stir, cover with a lid and leave on the lowest heat setting for 1 hour. You don’t want the onions to brown so check after 10 minutes to make sure all is well.
While the onions cook place tomatoes on a baking tray lined with baking paper. Sprinkle with sea salt and drizzle with the vinocotto olive oil combination, use your hands to gently toss, now scatter herb sticks over the tomatoes. Bake in oven for 1 hour 15 minutes.
Once cooked remove from oven and set to one side, increase temperature to 200C fan-forced (220C non fan) if cooking tart straight away.
Roll the puff pastry out a little further and use a 26cm dinner plate to cut a circle, score a border 2 cm from the edge. Brush the border with the egg wash.
Place pastry on a baking tray lined with baking paper, pop it in the fridge.
Meanwhile if the onions are cooked stir through the anchovies and capers then strain onions into a colander to remove excess liquid and leave to cool.
When ready to bake top the pastry with the cooled onion mixture, place in the oven at 200C fan-forced (220C non fan) for 15 minutes then reduce temperature to 180C fan-forced (200C non fan).
Continue to cook for a further 30 minutes then remove from oven and top with the tomatoes place back in the oven for 5 minutes.
Remove and top with random dollops of goat curd and sprinkle over parsley and preserved lemon.
Tip: The great thing about this tart is each component can be prepared in advance and then when ready to bake assemble and serve warm from the oven. Components you can prepare up to 1 day in advance: Slow cooked onions, slow roasted tomatoes and cut pastry (cover if leaving in fridge for more than an hour).