Preheat oven to 350. In a 2-quart saucepan, melt the butter and chocolate over very low heat, stirring constantly. Remove from heat and stir in the sugar, corn syrup, flour, vanilla, and salt. Continue stirring until the mixture is well blended. Add the eggs and mix well. Pour the filling into the unbaked pie shell. Set the pie on a cookie sheet and bake for 30 to 35 minutes or until the filling is puffed and the center is firm.
