1. Combine butter, evaporated milk, sugar and sale in a medium sized, heavy saucepan.
2. Bring to a boil over medium heat, stirring constantly.
3. Boil for 4 minutes, stirring constantly.
4. Remove from heat.
5. Stir in marshmallows, morsels, nuts and vanilla.
6. Stir until all is melted.
7. Pour into foil-lined 8" square pan.
8. Chill until firm and cut into pieces.