Frank says that this shake started with a surfeit of summer strawberries. When that season ended, they missed the milkshake made from them, so in the winter season, they invented this flavor.
To make the butterscotch, put 6tablespoons of the butter and the corn syrup in a heavy saucepan. Cook over medium heat for 5 minutes, stirring occasionally. Then add the brown sugar, granulated sugar, salt, and remaining 2