Preheat the oven to 180°C.
Warm up a heavy based fry pan. Add the butter and allow it to melt before adding the red onions. Stir with a spatula while sweating the onions down. Once the onions become transparent add the brown sugar and balsamic vinegar and stir through and cook for a further 6-8 minutes. Once the onions and balsamic vinegar become caramelised, remove from the heat.
Line a large flat baking tray with baking paper, lay the thawed out puff pastry on top.
Brush a 3cm boarder around the edge of the pastry with the lightly beaten egg wash.
Spoon the caramelised onions over the puff pastry and spread out to the boarder. Add the cherry tomato halves evenly over the caramelised onions then gently break up the goats cheese and sprinkle over the caramelised onions and tomatoes, followed by a good sprinkle of fresh thyme and sea salt.
Bake in the oven for 25-30 minutes or until golden and crispy.
Serve straight from the oven, season with a good pinch of cracked pepper, sea salt and a sprinkle of toasted pine nuts and extra fresh thyme leaves.