Melt butter in the microwave and set aside to cool.
Add cake mix, coconut, lemon zest and cooled melted butter to a bowl.
Mix until it forms a crumble that holds together when pressed but still crumbles easily.
Line an 8-inch square tin.
Press the majority of the crumble mixture into the base, reserving some for the topping.
Make the cheesecake filling by mixing cream cheese, caster sugar, Greek yoghurt (or sour cream), lemon juice and egg until smooth and lump-free.
Pour the cheesecake mixture over the prepared base and sprinkle the remaining crumble over the top.
Bake in a preheated oven at 170°C fan forced for 45 minutes.
The centre should still have a slight jiggle when removed.
Allow to cool on the bench, then refrigerate for a few hours until set.
Slice into bars and store in the fridge.
