Fill large, shallow pans with fresh, firmly packed snow. Set outside to keep the snow cold. Slowly boil a quart of pure maple syrup and 1⁄2 teaspoon of butter in a heavy pot, watching closely so it doesn’t boil over. When the syrup temperature reaches 234° on a candy thermometer (the soft-ball stage) take the pot outside. Using a spoon, quickly drizzle the hot syrup over the snow in patterns. (If the syrup doesn’t stay on top of the snow, it hasn’t cooked enough and will need to be reheated.) Kids love the drizzling part, but suit them up in old gloves and long-sleeved shirts so they won’t burn themselves.
Eat the maple candy when it hardens, or save it for later on sheets of greased waxed paper.