A small portion of cottage cheese with tinned peaches or fresh fruit. Mild, high protein, and requires zero effort.
Cottage cheese is one of the best emergency protein sources. If the texture bothers you, blend it smooth first.
Keep single-serve tubs in the fridge for zero-effort days. Tinned fruit in juice (not syrup) keeps the sugar reasonable.
Try ricotta for a smoother texture. Pineapple chunks also work well as the fruit component.