-
1
Preheat the oven to 450u00b0 F (425u00b0 F convection). Line a springform 9-inch cake pan with baking parchment.
-
2
Start by preparing the squash for the filling. Halve the butternut squash (you can leave the skin on) and remove the seeds. Wrap loosely in aluminum foil and roast in the oven, cut-side facing upwards, for 40 to 50 minutes ,until the flesh is soft. Once cool enough to handle, scoop out the pulp, place in a bowl and mash with a fork or potato ricer. You can do this a day in advance if you like and store the mashed squash in the fridge until needed.
-
3
Reduce the oven temperature to 350u00b0 F (325u00b0 F convection). Now prepare the base: Roast the hazelnuts on a tray for 8 minutes before removing. Rub with a clean towel to get rid of some of the papery brown skins, then crush to a rough crumb (you can use a food processor or chop with a knife). Melt the butter and set aside. Put the chopped hazelnuts and other remaining ingredients for the base (brown sugar, sea salt, cinnamon, biscuit crumbs) in a bowl, pour in the melted butter, and stir to combine. Tip the mixture into the tin and spread around to cover the base. Flatten a little but don't compress too much. Bake for 10 minutes, then allow to cool.
-
4
Place the cream cheese, sugar, and spices for the filling in a mixer with a paddle attachment (or use a large spoon, if making by hand). Work at a medium speed until well combined, then add the eggs one at a time. Finally add the butternut puree, flour, and sour cream and mix well. Pour over the base and bake for about 25 to 30 minutes. Remove from the oven and allow to rest and cool for 10 minutes.
-
5
Mix the sour cream for the topping with the sugar and vanilla seeds until you have a smooth paste. Pour over the top of the baked cheesecake, making sure not to pour it all in one spot, as it may sink in. Then use the back of a spoon or a small spatula to spread evenly over the top. Return to the oven for a final 10 minutes. Cool in the fridge for at least 6 hours (or overnight) before cutting and eating.
