Hello,
We have been doing overnight oats and that has worked very well. Here is a link to the recipe/formula,
The Little Epicurean | Overnight Steel Cut Oatmeal with Toasted Pecans and Caramelized Bananas. I make a batch of stewed fruit once a week (apples and pears these days) and use that to add in. We add no sweetener to the oatmeal, just water, steel cut oats and a pinch of salt. My fiance LOVES this. One pot will last him 3-4 days of breakfasts.
I also do another version of overnight oats that has rolled oats, and double the liquid (usually half milk/soy milk and half water) in a screw top tupperware and I leave it in the fridge overnight. I microwave it at work for three minutes and add frozen blueberries and almonds, which I take with me to work in a tupperware too. Works well and is very filling and nutritious. I use 1/3 c. oatmeal and 2/3 cup liquid.
I also do frittatas, which can be sliced and taken to work/eaten in the morning after reheating. You can also do the egg mixture and bake it in muffin tins, and take 2-3 of those for a breakfast. Coupled with a piece of fruit that makes for a good breakfast. I use 6 eggs and whatever veggies I have around. You can also add sausage to the egg and that adds even more protein... I use turkey or chicken sausage. Bake on 350 for 10-15 minutes and you have several servings you can take throughout the week. Keep the little egg muffins in the fridge for several days no problem. You can also do one big frittata in a skillet and take slices daily.
I also do tubs of homemade yogurt, or you can buy the bulk and/or individual servings of plain greek yogurt. I add fruit and nuts. I take all of this in tupperwares and just assemble at work.
Nothing may be quite as low maintenance as grabbing a muffin, but with a few minutes and some prep in advance, these are all healthy breakfast choices that are easy to do and very nutritious.
I also make a batch of granola once a week, and that goes on top of plain yogurt, also with fruit for an easy and portable breakfast.
These can all be packed up in a couple of tupperwares, assuming you have a fridge or can port things, they could work for you.
I prep most of these things on Sunday for the week.
Hope that helps,
Eva