Preheat the oven to 180°C.
Start by making the caramelised onion: slice the onion and place into a small saucepan with the butter onto medium heat.
Add the sugar and cook until soft and sticky, about 10 minutes
Meanwhile, lay out your puff pastry onto a floured surface and cut out rounds of desired sized and place the rounds onto a lined baking tray.
Slice the goat’s cheese into rounds. When the onion is caramelised, spread evenly onto the pastry. Lay the goat's cheese onto the onion and then top the tarts with smoked mussels and fresh thyme sprigs
Season the tarts and brush the edges of the pastry with milk and cook for about 25 minutes until pastry has puffed
Recipe reprinted with permission of Lucky Star