New York City restaurant Serendipity 3 already makes the world's most expensive sundae -- that would be the $1,000 Golden Opulence Sundae -- but the Upper East Side eatery can now also claim the world's most expensive hamburger, too. On May 22, Serendipity 3 set the Guinness World Record for the world's most expensive hamburger with its Le Burger Extravagant, a sandwich that will set you back $295, and likely several hundred calories.

Serendipity 3 says Le Burger Extravagant is available only for a limited time, and all orders for the world's most expensive burger must be placed at least 48 hours in advance. The restaurant said all profits from it would be donated to the Bowery Mission, which feeds and helps the homeless in New York City.

So what goes into Serendipity 3's high-priced hero? Let's break down the ingredients:

Japanese Wagyu beef: This extremely limited and costly kind of beef comes from Wagyu cattle, which are exclusively raised in Japan. Wagyu beef is known for its intense marbling, which makes the beef almost look like it's covered in snow, and the fat content enhances the beef's flavor, juiciness and tenderness. Due to the high demand but limited supply of this meat, Wagyu beef can cost between $100 to $150 per pound, and more, at least in the U.S. Serendipity 3's Wagyu beef is infused with 10 different herbs, as well as white truffle butter.

Salish Alderwood smoked Pacific sea salt: Salish smokes its salt over real alderwood, which gives it a great sweet and smoky taste with no strange aftertaste. Salish sells its smoked salts for roughly $11 for 4 oz. 

Aged cheddar cheese: You may think you've had cheddar cheese from just about everywhere, but you've never truly experienced cheddar cheese until you've tasted a sample from English cheesemaker James Montgomery from Somerset, England. Montgomery's cheese is given a lot of attention and care, and Montgomery is one of the few cheesemakers left in the world who still uses calf rennet to start the curd for the cheese and a slow peg mill to create the fissuring and brittleness of the cheese itself. Your cheddar cheese is cave-aged for 18 months and hand-formed before being placed on your burger.

Black truffles: While Serendipity 3 doesn't say what kind of black truffles are used in Le Burger Extravagant, truffles can cost anywhere from $30 apiece to $90, $100 and above. Some black truffles are known to cost $500 to $700 per pound or more.

Fried quail egg: Compared to chicken eggs, quail eggs are considered more of a delicacy due to their high salt and cholesterol content. On Le Burger Extravagant, Serendipity 3's chefs perfectly fry a single quail egg -- which costs slightly more than $1 per egg -- and perch it right on top of the burger. 

Gold-dusted campagna roll: This roll made of Campagna bread, which is a dense and chewy bread made of mostly white country French bread with a touch of whole wheat, is dusted with gold flakes and given a spread of white truffle butter on the bottom.

Topping the burger: On top of the finished burger, Serendipity 3 adds a small blini, which is a small pancake similar to a crepe, some crème fraiche -- essentially a less-sour cream -- and Kaluga caviar, which is similar to Beluga caviar in almost every way and costs about $80 per ounce. Speared through the blini, the crème fraiche and the Kaluga caviar is a Fleur de Lis toothpick, which is made out of solid gold and encrusted in diamonds.

So that's the burger! Remember that if you want to buy the world's most expensive burger, you have to act quickly -- Serendipity 3 is only selling Le Burger Extravagant for a limited time -- but you also have to act in advance, too. The restaurant requires a 48-hour notice in order to assemble the ingredients for your burger.

If you want to finish off the world's most expensive burger with the world's most expensive sundae, you're in luck: You won't even have to leave the restaurant. Serendipity 3's Golden Opulence Sundae comes with five scoops of ice cream with vanilla beans from Tahiti, chocolate syrup melted down from one of the world's most expensive chocolates called Amedei Porcelana, candied fruits, gold-covered almonds, chocolate truffles, marzipan cherries, an edible 23-carat gold leaf, gold flakes, and sugar paste for the sundae's floral decorations.