The 5-ingredient vintage recipe is shockingly good.Credit: Andy LyonsWhen I think of fair food, my mind usually goes to corn dogs, funnel cakes, and fried Oreos. Biscuits? Not so much. That’s why my interest was piqued when I stumbled across a century-old recipe for Fancy Baking Powder Biscuits from The Big E, the Eastern States Exposition in West Springfield, Massachusetts, a 17-day celebration of food, farming, and New England traditions. In 2…