Tiny detail sets McDonald's McDouble apart from the Double Cheeseburger

McDonald's is famous for their cheeseburgers, but many customers can't tell the difference between their two popular options: the Double Cheeseburger, and the McDouble .

The ingredients in both burgers are nearly identical except for one simple distinction- a single slice of melted cheese, Mashed reported . The Double Cheeseburger is made up of two all-beef patties, two slices of American cheese, pickles, dehydrated onions, ketchup, and mustard, all nestled between a split bun.

Meanwhile, the McDouble also has two beef patties , and the same standard toppings and condiments-pickles, onions, ketchup, and mustard — but only comes with one slice of American cheese, making it the slightly lighter item .

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That single slice of cheese makes a world of difference in terms of pricing. Although pricing varies depending on location, the Double Cheeseburger usually sells for around $4.19, while the McDouble is priced at around $3.65 - a 54 cent price gap.

The two items also vary in nutritional value, although slightly. The extra slice of cheese on the Double Cheeseburger increases the burger's caloric and fat content.

The Double Cheeseburger contains approximately 440 calories, 25 grams of protein, 24 grams of fat, and 1,120 milligrams of sodium in comparison to the McDouble, which has about 390 calories, 22 grams of protein, 20 grams of fat, and 920 milligrams of sodium.

The McDouble has actually only been around since 2008, when it was introduced as a response to the rising competition in the fast-food market and the increasing demand for affordable yet satisfying meals, compared to the Double Cheeseburger, which has been a staple on the McDonald's menu since 1965.

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Recently, a former McDonald's employee revealed the unexpected ingredients that go into the secret Big Mac sauce.

Ex-McDonald's corporate chef Mike Haracz revealed the unexpected list of ingredients that makeup the renowned burger sauce in a video uploaded to his account. Despite its characteristic pink color, there's no ketchup in the tangy condiment, according to Express. Instead, the mayonnaise-based sauce gets its distinctive taste from a blend of Dusseldorf mustard and white wine vinegar.

Mike said the orange hue comes from a small amount of paprika, which is used as both a dye and a flavor enhancer. Apart from mustard, vinegar, and paprika, the remaining ingredients are pretty standard, he said.

The secret to the Big Mac's iconic taste lies in its special sauce, a blend of mayonnaise, sweet pickle relish, onion powder, granulated garlic, and white pepper. Mike, a former employee, insists that mixing these ingredients and letting them sit for at least half an hour will yield a thick sauce that closely mimics the one used in McDonald's outlets, reports the Mirror .