Heat the butter, sugar, water and salt over medium heat in a saucepan fitted with a candy thermometer. Cook, stirring occasionally, until the mixture reaches 298 degrees F, about 10 minutes. Remove from the heat and stir in the vanilla and peppermint extract.
Immediately pour the mixture on the parchment paper and spread it out in an even thin layer. Let it cool completely.
Melt the chocolate and coconut oil in the microwave. I like to do this in 30 second increments, stirring after each time. Once melted, pour the mixture over the set toffee layer. Sprinkle in the crushed candy canes.
Let the chocolate layer set completely. You can store this in the fridge or at room temp. Break into pieces and serve!