Preheat oven to 200°C/fan 180°C/gas 6 and line 2 medium baking trays with baking paper.

Toss potatoes with oil, cumin and salt and pepper and arrange on one baking tray.

Place mushrooms on the other tray and season with salt and pepper. (Dont be tempted to add to the tray of potatoes as they may seep water and make your fries soggy!)  

Place both trays in the oven and bake for 15 minutes, or until potatoes are golden and tender. Scatter cheese over mushrooms and return to the oven for 2 minutes to melt cheese.

Meanwhile, combine beetroot and vinegar in a bowl. Season with salt and pepper and toss to coat.

Divide lettuce, tomatoes, avocado, beans, lentils, pickled beetroot and mushrooms between bowls. Squeeze over lemon, season and serve with sweet potato fries.