Pancake Day 2015 has arrived, signaling the onset of the Christian Lent season and sparking a flurry of social media posts on Tuesday from people partaking in the centuries-old tradition of making and eating pancakes before Ash Wednesday. Known formally as “Shrove Tuesday,” Pancake Day has historically been a time to load up on carbs before the 40 days of fasting leading up to Easter and is particularly popular in the U.K. The day celebrated by excessive pancake devouring is also observed in Australia, Canada, Denmark, France, Poland and Sweden.

The holiday has its roots in Slavic pagan festivals that were meant to ward off the evil gods of darkness and cold, according to Metro. The circular breakfast staple, whose origins date to the 15th century, symbolized the sun, conjuring feelings of warm weather and marking the beginning of spring. The ingredients involved in pancake making represented four pillars of the Christian faith -- eggs for creation, flour as the mainstay of the human diet, salt for wholesomeness and milk for purity.

The term “shrove” comes from an old English verb “shrive,” meaning “confess all sins,” according to the Cape Breton Post. It was seen as the last opportunity for religious observers to indulge themselves before giving up food for Lent. Pancakes were adopted as the Shrove Tuesday food of choice because they contain many of the things that were forbidden during Lent, including butter, fat and eggs.

An estimated 52 million eggs are used in Britain every year on Pancake Day, 22 million more than on any other day, the Telegraph reported. Pancake Day is typically marked by pancake races all over the U.K., during which participants carrying frying pans toss and flip pancakes while running toward a finish line. Points are given for the height of flips as well as best time. The races are a whimsical symbol for Christians’ rushing to church to repent of their sins after making pancakes.

While almost every country has its own version of the pancake, experts have said the perfect pancake is actually a hybrid of the French and British varieties. Adding a little leavening agent baking powder can result in a pancake that’s not too thin but not too thick, according to the Guardian. Pancakes should ideally be about the size of a dinner plate. The ideal accompaniments for pancakes include ice cream or whipped cream, which should be served on the side for dipping.