In a large bowl, using an electric/stand mixer (or hand whisk, just double/triple the times) combine the butter and both sugars on medium speed for several minutes, until fully combined. Add the egg and vanilla and mix again.
Add the flour, baking powder, white chocolate and fold until combined. The dough should be fairly solid at this stage (it ought to almost form a ball, albeit a very soft one!). Place in fridge to chill for 30 minutes.
Meanwhile, mix together the cheesecake filling and refrigerate .
Preheat the oven to 200C/180C Fan/Gas 6. Line 2-3 large baking trays. Roll into about 7 balls (use a tablespoon to scoop balls of dough). Place on lined baking sheets. Press down to be really flat, then place about a teaspoon of the cheesecake filling in the centre. Use your hands to roll the dough into balls, wrapping around the filling to keep it all in.
Place about 3 cookies on each baking tray - they spread a lot! Bake 12-14 minutes, until golden at the edges. Remove and let cool before eating!
