Hi Valerie,
Welcome back to the Disney Parks Moms Panel and thank you for your question. My experience with Walt Disney World Resort cast members is that they are as accommodating as they can be when it comes to special dietary requests. Last spring, we were dining at Garden Grill, and my young son didn’t like anything we were brought. Our server actually went downstairs to Sunshine Seasons to bring my son a Smucker's Uncrustables sandwich! She really went above and beyond to make sure he had something to eat, and it really relieved some stress on my part. I so appreciated the pixie dust she sprinkled on us that day.
While I don’t think there is an “official” answer to your question, I certainly know many people who have ordered an extra bun at Quick Service restaurants around Walt Disney World. It likely depends on the Cast Member serving you, as well as what they have in inventory at the restaurant. I would absolutely ask if this is possible when you order, and expect a charge for the extra bun. If for some reason this can’t be accommodated, perhaps you could cut the double cheeseburger in half to share? If you’re in Magic Kingdom Park, both
Pecos Bill’s Tall Tale Inn & Cafe and
Cosmic Ray’s Starlight Café offer extensive toppings bars, so you could add some delicious toppings to round out the meal.
I hope this answer was helpful, and that Disney pixie dust makes your double cheeseburger dreams come true.
Wising you a magical vacation,
Robyn