Ingredients
Method
Preheat oven to 210C. Line six 8cm tart cases with pastry and prick the base with a fork. Freeze for 30 minutes. Bake frozen tart shells for 10-12 mins or until dry and light golden, then cool on a wire rack.
Heat 2 tbsp of olive oil in a pan and add onions and garlic and cook over medium heat for about 5 mins, stirring occasionally, until softened.
Sprinkle in sugar and cook for 4-5 mins until caramelised. Add vinegar and season with salt and pepper. Remove from heat.
Toss mushrooms in a bowl with remaining oil. Transfer to an ovenproof dish, dot with butter, season and roast for 20-25 mins or until mushrooms are tender. Drain on kitchen paper.
Place onions in the bottom of warmed shells, add warm mushrooms and top with shaved parmesan.
To serve
Serve tarts on a bed of rocket and drizzle with extra balsamic vinegar.
