Preheat oven to 350°F. Place raisins in hot water for 10 minutes to soften. Drain well.
Whisk melted butter, sugar, corn syrup, maple syrup and eggs together in a large bowl.
Add vinegar, vanilla, walnuts and salt to the bowl and mix well.
Pour mixture into the pie shell. Bake for 25–30 minutes or until it is just set. Let cool fully before cutting.
