Cake:
Preheat the oven to 350 degrees.
Line two 9 inch round cake pans with waxed paper.
butter and flour the pans; tap out any excess flour.
In a mixer bowl, beat the butter until light and fluffy.
Gradually add the sugar and continue beating until smooth.
One at a time, beat in the eggs until well blended.
Sift together the flour, cocoa, baking soda, baking powder and salt.
Add to the egg mixture in thirds, alternating with the milk, mixing only until blended.
Blend in the vanilla and liqueur.
Divide the batter between the two prepared pans.
Bake until the tops of the cakes are springy to the touch, 40 - 45 minutes.
Remove from the oven and set on racks to cool for 30 minutes.
Loosen edges with a knife and unmold.
Peel off the waxed paper.
Cool completely on wire rack.

Filling:
Combine sugar, cream, chocolate, and corn syrup in a small heavy saucepan.
Bring to a simmer over moderate heat, stirring frequently.
Reduce heat to low and cook for 10 minutes, or until mixture thickens.
Remove from heat, dot top with butter, and let cool to room temperature, about 15 minutes.
When cool, stir in butter until filling is smooth and creamy.

Chocolate Cream:
Beat cream and cocoa until soft peaks form.
Gradually add powdered sugar and continue beating until stiff.

Assembly:
Cover one cake layer with all of the fudge filling.
Sprinkle evenly with 3 T chocolate chips.
Spread 1/2 c chocolate cream on top of chips.
Top with second cake layer and cover top and sides of cake with half of the remaining chocolate cream.
Use remainder in a pastry bag to decorate as desired.
Refrigerate up to 3 hours before serving time.

Syrup:
Combine cocoa, corn syrup, sugar, and water in a small heavy saucepan.
Bring to a simmer over low heat and cook, stirring constantly, for 2 minutes.
Transfer syrup to a small bowl and let cool to room temperature, stirring occasionally, to prevent skin from forming.
Just before serving, drizzle syrup over top of cake.