What Americans generally call Irish soda bread is not exactly a traditional recipe. Originally, Irish soda bread was made with a few simple ingredients: whole meal flour, buttermilk and soda. The bread was baked in an iron pot over the fire since most common folk did not have the luxury of an oven. For special occasions, perhaps the baker would add an egg, sugar, or raisins. The Americanized version of Irish soda bread is richer and sweeter than the original recipe, and usually contains raisins or currants. Some cooks add embellishments such as sunflower seeds, hemp or flaxseed, or honey. If you're interested in the history of soda bread, check out this interesting blog post by Shanore.