Step 1

Spread 1/3 of the peppermint candy over a 9x13-inch baking pan lined with wax paper.

Step 2

Melt the milk chocolate in the top of a double boiler over just-barely simmering water, stirring frequently and scraping down the sides with a rubber spatula to avoid scorching, just until melted. Pour the melted chocolate over peppermint candy in the prepared pan. Sprinkle another 1/3 of the candy on top of the milk chocolate. Refrigerate until the chocolate hardens, about 30 minutes.

Step 3

Melt the white chocolate in the top of a double boiler over just-barely simmering water, stirring frequently and scraping down the sides with a rubber spatula to avoid scorching. Stir in the oil-based peppermint flavoring. Pour the white chocolate over the milk chocolate, then spread the remaining 1/3 peppermint candy on top.

Step 4

Refrigerate until the white chocolate hardens, about 30 minutes. Cut or break into pieces to serve.