With a little practice, it's not hard to cycle fasted. I used to do 16 miles on a cup of coffee, another when I arrived, and finally something breakfasty mid morning.
But if you are looking for something simple to eat before you head out the door: Bircher müsli. Google for recipes, but in it's simplest form, just mix a handful of oatmeal with yoghurt before bed. In the morning just add a bit more yoghurt or some water to get it to the consistency you like. Then sugar, jam, lemon curd or (the night before) dried or fresh fruit, or just as it comes. It takes seconds in the morning, very good for you, a genuine tasty treat and - with a spoon and a screw top jar - can make a good breakfast when you arrive at work.
My favourite variant is a grated granny smith and a handful of dessicated coconut. Mixed with yoghurt the apple doesn't oxidise, so a single apple can make 3 days breakfasts.