Bagels and bialys are often lumped together. They're both round, chewy, and sold in shops around New York City. But these two staples of Jewish delicatessen cuisine differ in some major ways. Before celebrating National Bagel Day on Friday, January 15, make sure you know what you're ordering.

If you're familiar with just one of these products, it's likely the bagel. Bagels are round rolls with a hole in the middle and made from chewy, dense dough, according to Between Rounds Bakery Sandwich Cafe. Ingredients include malt, sugar, and wheat flour—all components missing from a bialy. After the dough is formed into a ring, bagels gets boiled and baked. This cooking process is what gives them their shiny, crunchy exterior. Bagels can be served plain or sprinkled with toppings like sesame seeds, poppy seeds, and chopped onions.

When eating a bialy, you'll notice one major difference right away: The food item doesn't have a hole. Rather, it has a depression in the center that can be filled with many of the same ingredients used as bagel toppings. Bialys are made with gluten flour instead of wheat flour and baked without being parboiled first. For this reason, their crust is more bread-like than smooth and shiny.

Eastern European Jewish immigrants introduced both bagels and bialys to the U.S. in the 19th and 20th centuries, but bagels have become the dominant cultural import. According to What's Cooking in America, only a handful of bakeries specializing in bialys operate in New York today, and the baked good is hard to find outside of the Empire State.

Fortunately for lovers of Jewish cuisine, bagels are much easier to get across the country (though their quality varies). Here are some facts to know about bagels in honor of their national holiday.

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