1. Cut the pumpkin into pieces and remove the seeds. Microwave it for 5 minutes to make it easier to peel.
2. Cut the flesh into cubes, put it in a saucepan, sprinkle with sugar and pour orange juice over it. Cook for about 20 minutes over low heat, stirring regularly.
3. Check the cooking of the pumpkin: it should easily mash with a fork. Pour the pumpkin into a bowl and puree it with an immersion blender. Unroll and spread the pie crust in a pie dish, keeping the parchment paper underneath. Reserve the crust in the refrigerator.
4. Whisk the eggs in a large bowl. Add the cream and cinnamon, mix well. Pour in the pumpkin puree and mix until smooth. Dry roast the pine nuts. Grate the lemon zest.
5. Prick the bottom of the pie crust with a fork. Pour the pumpkin mixture on top. Spread it evenly and smooth the top with a spoon.
6. Bake for 40 minutes in a preheated oven at 180°C (350°F). Remove the pie from the oven, let it cool slightly, and serve decorated with lemon zest and toasted pine nuts.