Actually I use many different tools ond each work. The tree looks more detailed than it is. I first shook cocoa onto the cup and then filled it up with espresso. Next step was using a stencil just for the stem and main branches using more cocoa to make it look dark. Then I used a second stencil for the leaves shaking larger pieces through it which gives you smaller and larger spots. It took me a few tries to get a good looking tree.
I always use a polarizer to reduce reflections on the cups.
Nice greetings :)