Mary Mccartney served up a tasty mushroom steak and chunky fries with beurre-less blanc sauce and watercress on Saturday Kitchen.

The ingredients for the chunky fries are: 700g russet potatoes, peeled and cut into 1cm-thick batons, 3 tbsp vegetable oil, flaky sea salt and freshly ground black pepper, For the beurre-less blanc sauce: 3 shallots, finely chopped , 4 sprigs fresh thyme, 1 tbsp olive oil, 240ml vegetable broth, 240ml dry white wine , 1 tsp cornflour, 1 tbsp Dijon mustard and 120ml unsweetened plant-based cream.

For the mushrooms: 4 large Portobello mushrooms, stems trimmed, 1 tbsp olive oil, 1 tsp garlic powder, 1 tsp chopped fresh thyme, pinch flaky sea salt and pinch freshly ground black pepper.

To serve: 150g watercress.

See recipes by Mary in her book titled: Food: Vegetarian Home Cooking available from Amazon now.