Look at any Scandinavian recipe that requires liquid sweetener and chances are that you'll be asked to use either "light syrup" (in Swedish, ljus sirap and also called bread syrup) or "dark syrup" (mörk sirap or dark bread syrup). It can be hard to get Scandinavian siraps in the United States, and they're not like maple syrup. Siraps are made from beet sugar. They are most similar to British golden syrup and treacle. As well, they are not wildly different from American molasses, which is also made from sugar.
In Scandinavian cooking, liquid sweeteners are often used for baked goods like gingersnaps, in candies, as a caramelization agent for sauce reductions, or in cabbage rolls. Light syrup is often used as a topping while dark syrup is used as an ingredient.
History of Scandinavian Sirap
Today, when you find Scandinavian sirap it is produced by Dansukker. Sugar was a luxury that only the aristocracy could enjoy at the time of the opening of Sweden's first sugar refinery in the middle of the 17th century. The raw sugar was produced from cane sugar grown in the New World and shipped to Europe to be refined. Prices lowered so the general population could afford sugar. The shipping blockage during the Napoleonic Wars led to discovering that sugar could be produced from beets. The abolishment of slavery in the mid-19th century led to a rise in cane sugar prices, making the sugar beet a viable alternative. The number of sugar refineries in Sweden grew to 10 at the start of the 20th century. They joined together to form the Svenska Sockerfabriks AB (SSA) company in 1907. The company changed its name over the years to Sockerbolaget AB in 1967, to Danisco Sugar AB in 1995, and to Dansukker in 2000.
History of Lyle's Golden Syrup
During the process of refining sugar, a light syrup is created. This syrup used to go to waste until chemist Charles Eastick perfected a way to refine the leftover syrup into a preservative and sweetener. Eastick worked for Abram Lyle & Sons, who began to market the product in 1885 under the name Golden Syrup. A deeply religious man, Abram Lyle chose the somewhat odd emblem of a dead lion covered in bees for the iconic image on golden syrup tins. The tins also bear the company slogan "Out of the strong came forth sweetness." In 2006, the "Guinness Book of World Records" deemed it Britain's oldest brand. The design of the tins has remained almost completely unchanged since 1885.
Where to Buy Light and Dark Syrup
Both light syrup and dark syrup are distributed by the Swedish Dan Sukker company; you can order them online from Scandinavian suppliers such as Scandinavian Specialties, or from Amazon. It's also sometimes available in stores that specialize in European foods or products, like Marina Market.
Substitutes for Scandinavian Light and Dark Syrup
Scandinavian light and dark syrups, unlike American "light" and "dark" corn syrups, are processed from sugar beets rather than corn. Thus, in most recipes calling for "dark syrup," you can generally substitute light molasses. The Swedish dark syrup is a bit sweeter and less bitter than American light molasses, but the taste is close enough that this substitution works well. Another option is to mix Lyle's dark treacle syrup with Lyle's golden syrup for a 50/50 blend.
Light syrup, however, really doesn't have a good U.S. equivalent. It's fairly thin (as syrups go) and sweet, with the distinctive flavor of brown sugar. You can substitute corn syrup in a pinch.