Preheat oven to 300 degrees F. and grease and line a 10-inch springform pan with parchment, then grease paper.
Pour freshly brewed coffee over chocolate and gently stir to melt. Set aside.
Sift sugar, flour, cocoa, baking soda, baking powder and salt and set aside. In a large bowl, beat eggs on high speed for 1 minute.
While beating, slowly add oil, buttermilk and extracts. Alternate adding flour mixture and chocolate mixture and beat until combined.
Pour batter into prepared pan and bake for 1 hour to 1 hour and 10 minutes, until a tester inserted in the centre of the cake comes out clean. Allow cake to cool for 20 minutes in the pan, then remove to cool completely.
For truffle glaze, place chocolate, butter and corn syrup in a bowl over barely simmering water and stir gently until melted and glossy. Stir in extract.
To assemble, trim barely ½-inch from outside of cake and slice in half horizontally. Place one layer of cake in bottom of clean 10-inch springform pan. Spread a third of the truffle glaze over the layer, pushing it over the sides of the cake. Top with second layer and spread all but ¼ cup of glaze over top layer, pushing glaze over sides. Chill cake for at least 3 hours before unmolding.
To unmold, press a hot towel around the sides of the cake to melt slightly. Loosen springform ring carefully, and run a spatula around side of cake smooth, if needed. Melt reserve glaze and drizzle over top of cake. Slice cake with a hot, dry knife and enjoy!