Preheat the oven to 200°C and grease a 25cm cake tin.
Roast 1kg of rhubarb pieces with 55g caster sugar for 20 minutes.
Roast the remaining rhubarb with one tablespoon of sugar until just tender.
Mix crushed ginger biscuits with melted butter and press into the tin base.
Beat cream cheese with 125g sugar, lemon zest, soured cream, and egg yolks.
Layer roasted rhubarb on the base and fold whisked egg whites into the cheese mixture.
Bake for one hour, reducing the heat to 180°C once the cheesecake rises.
Cool the cake, top with reserved rhubarb, and dust with icing sugar.