Place peppermint candy in a plastic bag. Use a rolling pin (or mallet) and crush the peppermint candy. Set aside
Turn the baking sheet upside down. Cover with aluminum foil. Set aside
Use half of the white chocolate chips and put them in a glass bowl in the microwave. Set on high for 30 seconds. Remove and stir the chocolate. Repeat in 15-second intervals, stirring each time, until the chocolate has melted.
Spread the melted white chocolate onto the baking sheet. Use a spatula to spread it evenly across. Drizzle with crushed peppermint candy. Chill for 15 minutes in the fridge.
Combine bittersweet chocolate, peppermint extract, and heavy cream in a small saucepan. Cook over medium-low heat until the chocolate begins to melt. Stirring constantly. Remove from heat and allow to cool for 2-3 minutes.
Remove the baking sheet from the fridge and pour the chocolate on top of the first layer. It's easiest to make three lines and spread each line. Work quickly, but not rushed. Return the baking sheet to the fridge and allow to chill for an additional 15 minutes.
Melt the second half of the white chocolate in the microwave using the method described above.
Spread the final layer of melted white chocolate on top of the hardened dark chocolate. Drizzle with the remaining crush peppermint candy. Refrigerate until hardened. About 15 minutes.
Cut the peppermint bark into triangles (or any other shape) and enjoy!