Scandinavian syrup is made from sugar beets. There are several kinds of Scandinavian syrups: Vit Sirap, Ljus Sirap, Mörk Sirap and Brödsirap. Most common in baking is Ljus Sirap (light syrup) and Mörk Sirap (dark syrup).
Ljus sirap is very similar to Golden Syrup (UK). In U.S there is no equivalent.
Dark syrup can be exchanged with Black Treacle in UK and with Light Molasses in U.S. Dark syrup is a bit sweeter and not as bitter as the American light molasses, but the taste is close enough.
Treacle
Treacle is any crystallised syrup made during the refining of sugar. The most common forms of treacle are Golden syrup, a pale variety, and a darker variety known as Black treacle. Black treacle, has a distinctively strong, slightly bitter flavour, and a richer colour than golden syrup. Golden syrup treacle is a common sweetener and condiment in British cookery.
A lesson in Molasses
Molasses is a sweet syrup that comes from the sugar cane, and is a byproduct of the sugar making process. The juice extracted from the sugar cane is boiled until some of the sugars crystallise out, and the juice will often be boiled up to 3 times to extract as much sugar as possible. What’s left is a thick, sweet syrup called, you guessed it, molasses.
The main types of molasses are:
Light: The syrup left after the first boil. It’s typically the lightest in colour, with a mild flavor. Most commercial molasses available in U.S. grocery stores is light molasses. And if it’s not labelled otherwise, you can assume this is what it is.
Dark: After a second boil, the molasses gets darker, more robust, and there are less sugars remaining the syrup. Molasses labelled Dark or Robust will have a stronger flavor and darker colour.
Blackstrap: The final byproduct left after the third boil. Blackstrap molasses is very concentrated, making it pungent, almost spicy with notes of licorice. It is also the darkest and most viscous of all varieties of molasses. Apparently it is very good for you, high in iron, so it is often sold at health food stores.
Sulphured: Made from young sugarcane, it has a much lighter and milder flavor than even your typical light molasses. The sulphur it is referring to is sulphur dioxide, a preservative. In my searching I was unable to find a true sulphured molasses; I would have loved to test out the differences in flavor!
Unsulphured: Most commercial molasses available in the U.S. is unsulhpured, and it is usually labelled as such. Unsulphured molasses is made from more mature sugar cane plants, and thus the preservative is not needed. You can find unsulphured molasses in all three grades (light, dark, and black).
Sorghum: Trick question! Sorghum isn’t molasses at all, but rather a similar product made from the sorghum plant. It’s much milder in flavor, and probably a bit tough to track down unless you live in the South. I already had way more cookies than I could even think of decorating, but maybe next year I’ll test out a batch using sorghum.
Source: http://www.loveandoliveoil.com/2012/12/classic-gingerbread-cut-out-cookies.html