a. Timbit
Bread: I used a UV ball as a base model, and used grad, inflate, smooth and so on to pinch the ball to make it look like real bread. In order to make an irregular surface, I modified the material with nodes function: using principled BSDF and noise texture and bump to create random bumps.
Chocolate topping: I copy the half-top area of the bread and solidify it.
Sugar spots: First, I made five small balls with different colours and used the geometry nodes function to “stick” the small balls on the distribution point of the chocolate topping. In order to make the position of the sugar spot more on the top and not coincident, I used wight paint and the Poisson disk.