This is my ideal, but not alwasy practical:
1. In camp eat 3-4 peaches, apples, or other fruit
2. After riding about 30 minutes or so stop to stretch and eat a banana or two
3. After another 30-45 minutes of riding I would stop and eat some nuts, granola, and maybe another banana
In the past I have opted for some cinnamon buns, pancakes, and other such high carb and sugary breakfasts, but I always crashed after a couple of hours.
If there is no fruit available then I would stick with granola, nuts, and oatmeal, but ideally i like to eat some fruits first thing, helps keep everything moving on tour, which is always a plus.