Combine crushed chocolate wafers, melted butter, and cinnamon in a medium bowl. Toss gently to mix. Press mixture onto the bottom and up the side of a 10-inch springform pan. Set aside.
Make the filling by combining cream cheese sour cream, sugar, and melted chocolate in a large bowl. Beat with an electric mixer on medium to high speed until smooth. Using a wooden spoon, stir in eggs just until combined. Stir in Baileys Irish Cream, pure cream and vanilla.
Pour filling into the crust-lined pan. Place springform pan in shallow baking pan. Bake for 50 to 60 minutes or until centre appears nearly set when gently shaken.
Cool in springform pan on a wire rack for 15 minutes. Using a small sharp knife, loosen from side of pan. Cool for 30 minutes more. Remove side of springform pan. Cool for 1 hour. Cover and chill for at least 6 hours.