When Making Onion Casserole, There's Only One Kind Of Onion You Should Use

If you're not from the Southeastern U.S., you might not know about onion casserole. That's a mighty shame, because it's an absolute delight. The concept is simple enough: It's a casserole made with a base of onions, eggs, evaporated milk, and cheese. It's topped with crackers — think butter over saltine — and baked until crispy on top and creamy in the middle. It combines savory with sweet to produce a seriously standout side dish (or main, we won't tell). Pair with a glass of Southern sweet tea and slow cooker pulled pork for a delicious dinner. There is, however, the matter of the onions. Here, there is really only one choice: Vidalia.

Onion casserole is a relatively simple dish to make, consisting of only a few ingredients, and taking only a few basic steps to construct and cook. Simply sauté onions, then add them in with evaporated milk, eggs, and cheese (the exact cheeses are up to your taste, though cheddar and parmesan are both popular choices). Top with cracker crumbs and bake. Voila! It's almost too simple to muck up. 

Vidalia onions, a sweet yellow onion variety, are the perfect choice for this casserole. Like other yellow onions, it has a milder flavor than white onions. Vidalias are even sweeter than your average yellow onion. Their subtle, sweet flavor allows for a more complex flavor profile that is less biting than what other onions provide. This, and its status as a Southern staple crop makes it the perfect choice for this dish.

One reason you'll want to go with Vidalia onions over other onions is based on the dish's, and veggie's, regional roots. Onion casserole is a Southern dish at its core, and it is built around Vidalia onions in particular. Created by farmer Moses Coleman, these onions are iconic to Georgia and the onion itself thrives in the sandy, Georgia soil. Using this sweet onion honors the Southern roots of the dish.

This brings us to our next point: flavor. It's Georgia's sandy soil that is said to give the onion its famously sweet and mild taste. Compared to other onions, Vidalias have a low sulfur and high sugar content, making them less pungent and more sweet. These flavors are perfect for an onion casserole, as the onion taste won't be too overwhelming. This is important, as your onions are the core of the dish. Their subtle flavor will play perfectly with a creamy base, cheese, and a buttery cracker topping. 

There is one hitch, however: Vidalia onions are highly seasonal, with the season running from mid to late April to September each year. You can find them at other times, though the flavor might not be as good. So, if you want to more fully enjoy your onion casserole, you might have to wait until summer. You'll be glad you did!