Add the sugar, ¾ cup butter and evaporated milk to a medium saucepan and apply medium-high heat.
Keep stirring until all is melted together, then bring to a boil.
Allow to keep boiling on a low roll (without stirring) for 5 minutes. You're looking for soft ball stage (235°F on a candy thermometer).
Add the marshmallow creme, chocolate, salt and vanilla and turn off the heat.
Keep stirring, the sugar mixture is plenty hot enough to melt all the chocolate and marshmallow creme.
Fold in the chopped walnuts, if you're adding.
Pour the fudge mixture into a 9x9" square baking pan, lined with parchment paper.
Shake it out so that it's even, then set down to cool for 3 hours.
After 3 hours, remove from the pan using the parchment paper and cut the Amish fudge into 1" cubes of deliciousness.
Notes
Adding nuts is completely optional, walnuts or pecans are common.There was a stage where a lot of Amish recipes used Margarine instead of butter - a lot of the Amish community do still use margarine - so if you're looking for a more authentic fudge - swap out the butter for margarine. I just happen to think it tastes better with butter.