Are you able to create one custom food (say, a serving of a specific brand of breakfast cereal), enter the information (usually on the box) and save it? That's what a custom food normally is - then you have the information and nutrition for that food.
If you are talking about a recipe, then that 'custom food' would have the information you have figured out by looking at the nutrition information of each component of the dish. For example: scrambled eggs, fried bacon, and fresh tomatoes. You would look at each item in the quantity you use, add the nutrition information for the three foods together (calories, iron, calcium, fiber, etc.) and create a custom food - 'egg and bacon tomato breakfast 1 serving' for example.
You'd enter the nutrition information for one serving, save it, and then in the future, when you wanted to count a serving of that breakfast, you'd find it in the custom foods database and add it to your log.
Which step has zeros?