Lightly grease a 8 x 10 baking pan and line with parchment paper making sure parchment overlaps sides for easy removal later. Set aside.
In a 8 quart pot combine sugar, evaporated milk, half & half and vanilla. Place pan over medium heat stirring constantly for 6 1/2 mins. Mixture should come to a rapid boil for a full 2 mins. Take off heat. Add butter and continue stirring while adding in chocolate chips. Stir until chocolate is melted and mixture is completely smooth. Stir in walnuts.
Pour chocolate mixture evenly into lined pan. Chill for at least 2 hours.
Once chilled gently run butter knife along sides of pan to loosen. Carefully remove fudge and loosen parchment from sides. With a large sharp knife carefully cut into small pieces. Keep refrigerated for a longer shelf life of up to 1 month.
92 calories per piece is with walnuts.
80 calories per piece without walnuts.