Tofu gives this nut roast a creaminess that makes it seem decadent. You can make individual portions or 1 big tart.
1. Preheat the oven to 180C/gas 4. Spread out the nuts and seeds on a baking tray and toast in the oven for 5–6 minutes. Transfer to a food processor, along with the chestnut purée, suet and maple syrup, and blitz until it comes together into a ball. It will be sticky to begin with, so stop and scrape the sides as you go.
2. Place a large sheet of baking parchment on a work surface and sit the dough on it. Then, with lots of gluten-free flour on your hands and rolling pin, roll out the dough as thinly as possible (less than 5mm).
3. If you’re making individual tartlets, oil and flour four 10cm loose-bottomed tart tins, then cut the pastry to size. For 1 large tart, roll out the dough and cut to the size of a large, shallow baking tin, and transfer to the tin using a fish slice. Prick the pastry all over with a fork, cover with baking parchment, fill with baking beans or rice and bake blind for 12–15 minutes. Leave to cool in the tray, and keep the oven on.
4. Meanwhile, make the topping. Heat 1 tbsp rapeseed oil in a pan over a medium heat, then sauté the mushrooms for 6–8 minutes, until golden. Remove and set aside.
5. In the same pan, heat the rest of the oil and wilt the spinach (or heat through if frozen) along with the pepper. Blitz the spinach, avocado flesh, tofu, nutmeg and lemon juice in a food processor until smooth.
6. Thinly slice the sweet potato using a vegetable peeler or mandolin, creating a pile of peelings. Heat a drizzle of olive oil in a small pan, then fry the peelings over a high heat, turning occasionally, for 4–5 minutes, until just turning crisp.
7. Assemble the tart by spreading the spinach mixture over the baked and cooled tart base. Lay the mushrooms on top, and decorate with the sweet potato slivers and a scattering of toasted pine nuts. Eat heated or at room temperature, with potatoes and vegetables.