We always used our snack credit for breakfast since we can't stomach a huge meal in the morning.
Most mornings we purchased a yogurt parfait (at our resort, CSR) that had yogurt, granola, & fruit layered. It was super filling. One morning we each got a muffin...they are large but didn't fill us up for any length of time like the yogurt parfaits did. One of the days we spent in MK, on our way out that evening we got one of their giant cinnamon rolls at Main Street Bakery and shared that the following morning. Again, the cinnamon rolls didn't fill us up for hours like the yogurt parfait did, but it was super yummy!