Preheat oven to 350° F.
Spray a 9″ square baking dish with cooking oil spray, and dust with flour.
Melt unsweetened chocolate and butter in a double boiler, stirring frequently until smooth.
Cool to room temperature.
While the chocolate is cooling, in a large bowl, beat eggs, sugar, vanilla, and peppermint extract until well combined.
Beat in the chocolate mixture.
Slowly, stir in flour.
Pour batter into greased pan.
Bake in the oven for 45 minutes.
Test brownies with a toothpick for doneness.
Arrange mint chocolate squares on top of brownies.
Return to oven for just a minute or two, until mint squares are soft/melted.
Use a spatula to spread mint squares across all brownies.
Sprinkle crushed candy canes on top.
Allow to cool before cutting and serving.