Preheat oven to 350° F. Grease and flour a 12-cup bundt pan. Set aside.
Place unsweetened chocolate and cocoa powder in a small bowl. Carefully pour in boiling water and stir until melted and smooth. Set aside.
Combine flour, baking soda, and salt in a bowl and set aside.
Pour peppermint schnapps into a 2-cup glass measure with a pour spout. Spoon in sour cream until the schnapps and sour cream reach the 1 1/2 cup line. Mix well and set aside.
In the bowl of a standing electric mixer, cream together butter and sugar until light and fluffy.
Add the eggs to the butter mixture one at a time, beating well after each addition. Beat until well blended. Add the peppermint extract and melted chocolate. Stir to mix.
Alternate adding the flour mixture and sour cream-peppermint mixture to the egg-butter-chocolate mixture in several additions. Stir until well combined. Gently mix in chocolate chips.
Scrape the batter into prepared bundt pan, smoothing the top to even out the batter. Bake for 55 to 60 minutes, until the cake is firm to the touch and a skewer inserted into the center comes out with just a few crumbs clinging to it.
Remove from the oven and cool the cake for 30 minutes in the pan. Carefully turn the cake out onto a rack and cool completely.
For the glaze, place dark chocolate in a 2-cup measuring glass with a pour spout. Bring cream to a boil in a small saucepan over medium heat. Pour cream over the chocolate and let it sit without stirring for two minutes before mixing vigorously with a small spatula. Once the chocolate becomes smooth and glossy, add peppermint extract and mix until smooth.
Set the rack holding the cooled cake atop a baking sheet. Stir the ganache well before slowly drizzling the glaze over the cake. Allow the glaze to set. Right before serving, sprinkle with crushed candy canes if desired.