1 can (5 oz) evaporated milk
1 1/2 cups packed light brown sugar
5 oz. (1 1/4 sticks) unsalted butter
1/4 tsp salt
1/2 cup confectioners sugar
1 tsp pure vanilla extract
3 oz. toasted walnuts, chopped
Coat a 5 x 10 inch loaf pan with cooking spray. Line with plastic wrap leaving a 2 inch overhang on 2 sides. Bring Evaporated milk, brown sugar, butter, and salt to a boil in a medium saucepan, stirring constantly. Reduce heat to medium low and simmer, stirring frequently, until mixture registers 236 degrees, about 25 minutes. Transfer to a mixer bowl, and beat in confectioners sugar on low speed. Scrape down sides of bowl as needed. Increase speed to medium and beat and beat until mixture is thickened and smooth, 2-4 minutes. Reduce speed to low, and add vanilla and walnuts.
Spread mixture in pan, smoothing top. Refrigerate uncovered, until firm about 25 minutes. Un mold fudge using plastic overhang and discard plastic.