Today’s Wonder of the Day was inspired by Lisa. Lisa Wonders, “Who made the first Philly cheese sub?” Thanks for WONDERing with us, Lisa!

When some people travel, they look forward to being able to eat certain foods that are specialties in the place they visit. For example, visitors to New Orleans often can't wait to eat beignets for breakfast. Likewise, visitors to Maine might feast on lobster, while those in Chicago might sample some deep-dish pizza.

But what if you visit Louisville, Kentucky? If you come for the Kentucky Derby or visit on vacation, you'll want to make sure you try the sandwich that was born in Louisville: the Hot Brown.

In the early 1920s, late-night diners often feasted on ham and eggs after dancing the night away at the Brown Hotel in Louisville. Looking for an alternative to tempt his diners, Fred K. Schmidt of the Brown Hotel created a new signature sandwich in 1926.

The Hot Brown is an open-faced sandwich (eaten on a plate with a fork rather than with the hands) that features turkey and bacon. It is smothered in Mornay sauce, which is a rich, creamy combination of milk, butter, flour, and a mixture of cheeses.

A Hot Brown is served hot, after it is baked or broiled until the bread is crisp and the sauce begins to brown. There are many variations on the basic Hot Brown. Some chefs include ham with the turkey. Others sprinkle pimento peppers or tomatoes over the sauce after it has been browned.

Vegetarians can even have their own version of a Hot Brown by substituting avocado or soy burger for the meats. If you don't know how to make Mornay sauce, you can also substitute Cheddar cheese or a store-bought cheese sauce instead.

In Louisville, the sandwich is usually referred to as a “Louisville Hot Brown." Around other parts of Kentucky, you may see it called a “Kentucky Hot Brown." In other areas of the country, it's just a “Hot Brown."

Another city famous for a signature sandwich is Philadelphia. In the 1930s, brothers Pat and Harry Olivieri began serving chopped steak sandwiches in hoagie rolls. The Philly cheesesteak sandwich became so popular that Pat opened his own restaurant — Pat's King of Steaks — and it's still open today!

Although the sandwich was originally served without cheese, “Cocky Joe" Lorenza began adding Provolone cheese, and melted cheese is now an essential part of the sandwich. Today, you can find variations of cheesesteaks in restaurants all around the country.

Variations on the traditional Philly cheesesteak include different types of cheese, sautéed onions, bell peppers, mushrooms, mayonnaise, hot sauce, and ketchup. Some variations even involve changing the meat from beef to chicken or turkey.

What regional specialties are popular in your area? Do you have a favorite food you look forward to eating when you go somewhere special on vacation?

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