Preheat the oven to 200C/180C Fan/Gas 6. Line an 8 inch square baking tin.
Combine the melted butter, granulated sugar and light brown sugar in a large mixing bowl or the bowl of a stand mixer. Combine on high speed for 3-5 minutes.
Add the eggs and vanilla and combine again.
Fold in the flour, baking powder, lemon zest and white chocolate chunks, using a wooden spoon/silicone spatula. Pour this mixture into the lined tin and spread out evenly.
In a separate bowl, combine the cream cheese, sugar, egg and the juice of 1 lemon. Pour this over the blondie. Bake for 30-35 minutes. The cheesecake may appear a little wobbly - a little is okay, if it looks VERY wobbly give it another 5 minutes. Let cool for at least 1-2 hours before slicing and serving!