Line and 8x8 or 9x9 inch square pan with aluminium foil. Set aside.
In a large heavy bottom sauce pan, melt the butter, sugar, whipping cream, marshmallow cream & salt.
Once almost melted bring the mixture to a boil over medium-low to medium heat while stirring constantly. Once the mixture starts to boil, continue stirring until the mixture reaches 238F degrees or it boils for a full 5 minutes.
Remove from the heat and add in the white chocolate and peppermint extract. Stir until the chocolate is completely melted.
Pour the mixture into the prepared pan and sprinkle with crushed candy canes. Allow the fudge to harden at room temperature for 2-3 hours. Once the fudge is no longer hot - you can let wrap tightly and let it harden in the fridge. Carefully remove the fudge from the pan by lifting out the edges of the foil. Cut into small squares using a sharp knife.
Fudge is best if stored in the refrigerator in an airtight container