adapted from: Tips from a Typical Mom
2 c. heavy whipping cream
4 c. sugar
3 (4.25 oz.) Symphony Bars (milk chocolate bar with almonds and toffee)
2 sticks (16 Tbl.) unsalted butter, cut into cubes
1 c. mini marshmallows
2 tsp. vanilla
Line a 9x13-inch pan with parchment paper and lightly spray with cooking spray; set aside. Add whipping cream and sugar to a large saucepan and whisk until combined. Make sure to use a large pan or your mixture will boil over. Heat over medium heat, stirring frequently, until mixture comes to a boil. Let the mixture boil for 10 minutes and DO NOT STIR WHILE BOILING.
Meanwhile, to the bowl of a stand mixer (or large bowl), break up the candy bars and add to the bowl along with the cut up butter, marshmallows and vanilla. After the sugar mixture has boiled for 10 minutes, remove from heat and carefully pour over the chocolate mixture in the bowl. Do not scrape the edges of the pan (we don't want sugar crystals in the fudge). Start mixer on low speed and gradually work your way up to medium speed. Mix until everything is well combined and mixture is smooth and starts to lighten in color.
Pour into prepared pan and spread out evenly. Allow to cool for one hour, then cover and refrigerate until completely cool. Cut into squares and serve. I like to store the leftover fudge in the refrigerator and then bring it to room temperature before serving.