Mushroom, spinach, kale and sweet potato pie Author: Just Add Mushrooms Serves: 4 Ingredients 2tbsp olive oil 500g closed cup mushrooms, thickly sliced (Matthew Hall recommends oyster mushrooms as an alternative) 2 cloves garlic, crushed 250ml vegetable stock 300g cooked sweet potatoes, cut into chunks Salt & freshly ground black pepper 2tbsp light crème fraîche