1Preheat the oven to 200°C. Line a large baking tray with baking paper. Top with a piece of puff pastry (plastic sheet backing removed), then use a sharp knife to score a 1 cm border around the edges of the pastry (see note). Bake for 20-25 minutes, or until golden and puffed. Remove from the oven and allow to cool.
2While the pastry bakes, heat half the olive oil in a large frying pan over medium-low heat. Add the onion and cook for 10 minutes, until softened. Stir in the balsamic vinegar and brown sugar and cook for a further 5 minutes, or until caramelised.
3Heat the remaining oil in a second large frying pan over medium-high heat. Add the mushrooms and thyme and cook, stirring for 8-10 minutes, or until tender. Season well with salt and pepper, then remove from the heat.
4Using the back of a spoon, carefully press down on the centre of the tart, flattening the centre, allowing room for filling, but leaving the edges puffed. Spread the base of the tart with caramelised onions, then top with the mushrooms. Sprinkle with the crumbled goat’s cheese.
5Return to the oven for an extra 5-10 minutes to slightly melt the cheese. While the tart bakes, in a large bowl, combine the ingredients for the cherry tomato salad, seasoning to taste with a pinch of salt and black pepper.
6Remove the mushroom and goat’s cheese tart from the oven and cut into slices. Serve with the cherry tomato salad on the side.
Note: If you are unsure of scoring the edges of the pastry, you can cut a second sheet of puff pastry into long strips. Use these strips to create a border around the first sheet, brush with egg wash and bake until puffed and golden.
