Mushroom and Goat's Cheese Burger

Halve, peel and thinly slice the red onion. Heat a drizzle of oil in a large frying pan on medium-high heat. Once hot, add the onion, season with salt and pepper and fry until soft and sweet, 8-10 mins. Add half the balsamic vinegar with a pinch of sugar (if you have some) and cook until the balsamic has evaporated, 1-2 mins. Transfer to a small bowl and set aside. Wipe out the pan for later.

Remove the stalk from the portobello mushrooms (but leave the mushrooms whole). Return the frying pan to medium-high heat with a drizzle of oil. Add the mushrooms to the pan and season with salt and pepper. Fry until golden brown, 3-4 mins, then turn over and cook for a further 3-4 mins.

About 10 mins before the wedges are cooked, move them to the middle of the oven. Transfer the mushrooms (stalk side up) onto a baking tray. Divide the goat's cheese between the mushrooms, then bake on the top shelf until the cheese has melted, 8-10 mins. Meanwhile, cut the ciabattas in half, then pop into the oven for the last 3-4 mins to toast.

Meanwhile, pop the remaining balsamic vinegar and a drizzle of oil into a bowl. Season with a pinch of salt and pepper, then mix together. Just before the mushrooms are ready, add the rocket to the dressing and toss to coat.