Polenta with garlicky mushrooms & leeks

Heat 1 tbsp oil in a frying pan over a high heat and add the mushrooms; fry for 5 minutes, then stir in the garlic and cook for 1-2 minutes more. Season, transfer to a plate and keep warm. Heat the remaining 1 bsp oil in the same pan and add the leek with a pinch of salt. Cook over a medium heat for 10 minutes until softened, then transfer to the plate with the mushrooms.

Meanwhile, bring a pan of water to the boil and add the cavolo nero. Cook for 3-4 minutes until wilted, then drain and transfer to a bowl of iced water. Drain again, squeezing out as much water as you can and put in a blender with the parsley (leaves and stalks), nutritional yeast and   tbsp oat drink. Season, then whizz to make a purée (add extra oat drink if needed); set aside.

In the same pan, bring 125ml water and 125ml oat drink to a simmer. Add the polenta and cook over a medium heat, whisking constantly, for 3-4 minutes. Turn the heat right down and cook for a further 5-10 minutes until thick and creamy. Stir through the purée and season, then spoon onto a plate and top with the mushroom and leek mixture. Scatter with extra parsley, the walnuts and lemon zest. Squeeze over the lemon juice to serve.