Pesto & Mozzarella Portobello Burger

Meanwhile, remove the stems from the portobello mushrooms (but leave the mushroom whole).

Heat a drizzle of oil in a large frying pan on high heat.

Once hot, fry the mushrooms until golden brown, 4-5 mins, then turn over and cook for a further 4-5 mins. Transfer them, stem-side up, to another baking tray.

While the mushrooms are frying, halve, peel and thinly slice the onion.

Heat a drizzle of oil in a medium saucepan on medium heat.

Once hot, add the onion, season with salt and pepper and fry, stirring occasionally, until golden, 10-12 mins.

While everything fries, drain the mozzarella and squeeze out as much liquid as you can. Pat dry with kitchen paper, then tear into small pieces.

Divide the mozzarella between the mushrooms. Drizzle over the pesto and season with salt and pepper.

Bake on the middle shelf of your oven until the cheese has melted, 8-10 mins.

Meanwhile, once the onions are golden, add the sugar (see pantry for amount) and balsamic vinegar. Cook until caramelised, 1-2 mins more.

Halve the burger buns. Pop onto the baking tray with the mushrooms and back into the oven to warm through, 2-3 mins.