my please!
look at this thread it will inspire you a lot :
I think using the translucent BSDF/ or the subsurface of the principled BSDF will help with that:
even tho there is a space where the paper sticks out, feels like a thicker paper too than yours and stayed clean from the outside
based on your model and reference, you have no space but still i will give subsurface a try, and the paper in your reference looks like it have more permeability and cake material went through.
maybe a mix shader between paper material and cake material driven by a map that you paint that noise/dots where the cake passed thorough the paper and using it to to drive also a bump/displacement (adding pointiness to mix can help to emphasis the effect based on the paper folds)
a quick tutorial about mixing shaders:
