Yes, this is often an option!
If you're eating at a buffet restaurant that serves both breakfast and lunch, you can make a late breakfast reservation (around 10:30 or 10:45), and you'll get to not only eat items from both breakfast and lunch, but you'll end up paying the breakfast price.
Just be sure to check in on time so that when they give you the receipt for your meal at check in, it's for breakfast.
Another good breakfast dining trick is to eat at a place before park opening that often lets you ride something afterward but before the park opens. Learn how the breakfast/ride combo works to see if you want to try it during your trip.