1. Pre-heat the oven to 200°C/gas 6.
2. Place the chopped pumpkin into a baking tray. Dot with butter, sprinkle over the caster sugar and drizzle with the syrup. Bake in the oven for 30-35 minutes until the pumpkin is soft.
3. In a small processor crush the ginger nuts until they look like breadcrumbs. Add the melted butter and mix well.
4. Line a baking tray with parchment. Place 4 metal rings on the tray. Divide the ginger nut mixture between the bases. Using the back of a spoon press the mixture down well.
5. Take the roasted pumpkin and any cooking juices and place in a processor. Blitz until smooth. Taste the puree and add more sugar if required.
6. Mix the whipped cream, cream cheese and yogurt together. Add the stem ginger and mix well.
7. Take the pumpkin puree and swirl it through the cream mixture, then place into the rings. Smooth over the tops and leave in the fridge to set.
8. To serve remove the rings and decorate the tops of the cheesecake with extra stem ginger.