Create your characters. At the heart of good stories lie interesting, likable characters with whom readers can identify. You can make your main character a seasoned pastry chef or a child who's just learning to bake. She can have a baking assistant or the story can be all about her. Write down your characters' names and a brief description of what each of them looks like and any unique characteristics they may have.
Develop your plot and write a short outline. Everything can go smoothly with the baking of the cake, or you can write a story in which everything falls to pieces (the chef adds salt instead of sugar, or the cake sits in the oven too long and burns). Your story doesn't need to be very long, but older children may enjoy more detail and description. If you're writing for children younger than 6 or 7, keep the plot very simple.
Thumb through cookbooks or look online to find a simple cake recipe. Easy-to-make cakes include butter cake, pound cake, basic chocolate cake, white or yellow cake and carrot cake. Also find a simple frosting recipe such as buttercream, cream cheese, vanilla or chocolate.
Write your story. While writing, refer to your recipes and include each step. If things go wrong with the baking of the cake, be sure to let the reader know which mistakes were made. If you have more than one character, consider using dialogue to move the story along and keep your readers engaged. For example, if a father and son are baking together, he can ask the child which ingredients he thinks go into the cake or he can praise the child for doing a good job.
Include illustrations where appropriate. Don't worry if you're not a great artist. Simple, colorful magic-marker drawings will help keep young readers interested in your story. Make sure to include a final drawing of what the finished cake should look like.
Write out the cake and frosting recipes and include them at the end of your story. If your original recipes use any complicated language, simplify it so that children easily follow the directions under adult supervision.