Preheat the oven to gas 9, 240 degrees Celsius, fan 220 degrees Celsius. Greaseproof paper the base of a 23cm round springform nonstick tin. One of the pastry sheets should be cut in half. One half should be set aside. Combine the other ingredients with the entire sheet and roll out to a 35cm × 35cm square, 1cm thick, on a lightly floured surface. Gently press the pastry into the bottom and up the sides of the tin, overlapping the edges at the top. While you're making the filling, put it in the fridge.
In a medium pan, heat the oil and cook the onion with a touch of salt for 5-7 minutes, or until transparent. Cook for 2 minutes after adding the fennel, garlic, and bay. Stir in the rice until it is evenly coated. Cover with 350ml water, come to a boil, then reduce to a low heat and cook for 10 minutes.
Meanwhile, in a food processor, blitz the nuts until they're finely chopped but still have some texture. The rice should be cooked and have absorbed all of the water after 10 minutes. Remove the pan from the heat and add the nuts and lemon zest. Allow time for cooling.
Bring a pot of salted water to a boil for the cauliflower. Boil the cauliflower for 212 minutes after cutting it into small florets. Drain and place on a baking tray. Roast for 15 minutes, turning halfway through, in a preheated oven with the oil, cumin, and chili. Turn the oven down to gas 6, 200°C, fan 180°C, and set aside to cool.
Combine the cranberries, sugar, and apple juice in a pan. Bring to a low simmer to enable the sugar to dissolve, then remove from the heat and allow the pan to boil. Remove 6 tbsps to a small bowl to decorate the top after 4 minutes. Allow the rest to bubble for 4 minutes before setting it aside to cool.
Layer the ingredients in the pie dish once they've cooled. Half of the rice should be poured into the base and pressed down to compact it. Place the roasted cauliflower on top of half of the cooled cranberry sauce. Finish with the last of the rice.
Brush the pastry's overlapping edges with beaten egg. The remaining pastry sheet half should be rolled out into a 25cm (10in) circular. Place the circle on top of the pie and trim the extra around the sides with a knife. To crimp and seal the pie, press down around the edges. Cool for 20 minutes after brushing the top with beaten egg. (The pie can be made up to this point a day ahead of time.)
Preheat the oven to 350°F and bake for 50 minutes, flipping halfway. Remove the cake from the tin and place it on a serving platter. Serve the leftover sauce as an accompaniment and garnish with the reserved cranberries. Serve with a green salad or wilted greens, cut into wedges.