1. Bring a large saucepan of water to the boil and blanch each cabbage leaf for 2 minutes. Plunge each one into a bowl of ice water to refresh them and prevent them from cooking any further, set aside for a few minutes
2. In a food processor, blitz the chestnut mushrooms, leek, onion and chestnuts until the mix is finely chopped
3. In a frying pan, heat the rapeseed oil and add the garlic, cook for a minute or so. Add the chopped vegetables, spinach and thyme, and stir for approximately 5 minutes. Add the cooked rice and combine
4. Allow to cool slightly

For the marinara sauce

1. Preheat the oven to 180C
2. In a saucepan, heat the oil and add the onion and garlic. Cook for a few minutes, until the onion has softened
3. Add the tinned and sundried tomatoes, oregano, vegetable stock and tomato puree, and bring to the boil. Reduce the heat and allow to simmer for a few minutes. Add the basil leaves and brown sugar and stir until the leaves wilt and sugar dissolves
4. To assemble the stuffed leaves, place a blanched cabbage leaf on a clean board with the cut end closest to you. Place 2 large spoonfuls of mixture towards the uncut end, fold the sides inwards and roll away from you like you would if making a burrito. Repeat with the remaining leaves and filling
5. Spoon half of the marinara sauce in the bottom of a flat-bottomed, lidded baking dish and arrange the stuffed leaves on top of the sauce, cover with the lid and place in the preheated oven for 25 minutes
6. Remove the pan from the oven and serve the stuffed leaves with some of the remaining marinara sauce