Can be cooked from The Fresh Plate Cookbook.
There are 4 recipes in this file. They all will look like plain chocolate doughnuts when you make them so you'll need to actually decorate them. When your Sims decorate them they'll have a chance to get 1 of 3 patterns for each doughnut type:
Halloween Doughnuts - basic coat of frosting with 3 color variations
Cute Halloween Doughnuts - ghost, vampire, frankenstein
Creepy Halloween Doughnuts - eyeballs, monster, spiderweb
Candy Corn Doughnuts - candy corn pattern with 3 color variations
All of these doughnuts will stack in the same pile like bread loaves, so this should keep your inventory from getting too cluttered.
NOTE: I will be updating these in the future with ingredients and adjusting the retail amounts based on those ingredients in the near future.